Related
var myString = "$guid$! test $guid$, here another test string and then $guid$";
by using
myString.Replace("$guid$", Guid.NewGuid().ToString()))
the value for every found guid will be the same, how to change for every found new value?
You could use Regex.Replace:
var replaced = Regex.Replace(myString, #"\$guid\$", match => Guid.NewGuid().ToString());
The match evaluator will be called for every match and can easily return different replacements for each call
I create a tiny extension method that match the currents one
/// <summary>
/// Returns a new string in which all occurences of a specified string in this instance are replaced with a runtime determined string
/// </summary>
/// <param name="oldValue">the string to be replaced</param>
/// <param name="newValue">the function used to replace the string called one time per occurence</param>
public static string Replace(this string text, string oldValue, Func<string> newValue)
{
var replacedText = new StringBuilder();
int pos = text.IndexOf(oldValue);
while (pos >= 0)
{
var nv = newValue();
replacedText.Append(text.Substring(0, pos) + nv);
text = text.Substring(pos + oldValue.Length);
pos = text.IndexOf(oldValue);
}
return replacedText + text;
}
I don't know why there is no existing C# function like this but it works nice.
I make a tiny unit test with your example (using NFluent) :
[TestMethod]
public void ReplaceTest()
{
var i = 1;
Check.That("$guid$! test $guid$, here another test string and then $guid$"
.Replace("$guid$", () => (i++).ToString()))
.IsEqualTo("1! test 2, here another test string and then 3");
}
I want to allow user so they can read more than one tag in a string. So far, user could only add one tag
if (rtb.Text.Contains("[b]"))
{
Regex regex = new Regex(#"\[b\](.*)\[/b\]");
var v = regex.Match(rtb.Text);
string s = v.Groups[1].ToString();
rtb.SelectionStart = rtb.Text.IndexOf("[b]");
rtb.SelectionLength = s.Length + 7;
rtb.SelectionFont = new Font(rtb.Font.FontFamily, rtb.Font.Size, FontStyle.Bold);
rtb.SelectedText = s;
}
else if (rtb.Text.Contains("[i]"))
{
Regex regex = new Regex(#"\[i\](.*)\[/i\]");
var v = regex.Match(rtb.Text);
string s = v.Groups[1].ToString();
rtb.SelectionStart = rtb.Text.IndexOf("[b]");
rtb.SelectionLength = s.Length + 7;
rtb.SelectionFont = new Font(rtb.Font.FontFamily, rtb.Font.Size, FontStyle.Italic);
rtb.SelectedText = s;
}
richTextBox1.Select(richTextBox1.TextLength, 0);
richTextBox1.SelectedRtf = rtb.Rtf;
If i have this string:
"Hello [b]World[/b] Meet the [b]Programmer[/b]"
the output would be like this:
"Hello World Meet the Programmer"
And if i have this string:
"Hello [b]World[/b] Meet the [i]Programmer[/i]"
the output would be like this:
"Hello World Meet the [i]Programmer[/i]"
How to read multiple tags from a string? like, in a string if i have 2 [b][/b] tags, 5 [i][/i] tags or even mixed tags ([b][i][/i][/b])?
Two problems:
1. Greedy matching semantics of Regex
\[b\](.*)\[/b\] looks for the longest possible match within your string, i.e. it is greedy. In your example, you expect it to match [b]World[/b], when in fact it matches [b]World[/b] Meet the [b]Programmer[/b] (consequently making "Meet the" bold as well). This can easily be resolved using non-greedy syntax: \[b\](.*?)\[/b\] (note the extra ?)
Details: How to Match with Regex "shortest match" in .NET
2. You are only looking for one occurrence of tags!
Obviously, your code will only highlight a single [b]/[i] tag. Don't use else if if you want [i] to be handled if your string contains [b]. Use loops and Regex.Matches if you want to handle all occurrences of your regular expression instead of just the first one.
Without Regex but still must be adapted slightly.
The test:
[Test]
public void Text()
{
string str = "[b]Hello[/b] This is sample text [b] Goodbye [/b]";
var bold = AllIndexesOf(str, "b").ToArray();
// Assume the IEnumerable is even else it should of thrown an error
for (int i = 0; i < bold.Count(); i += 2)
{
Console.WriteLine($"Pair: {bold[i]} | {bold[i+1]}");
}
// str.AllIndexesOf
}
Here is the method.
/// <summary>
/// Courtesy of : http://stackoverflow.com/a/24016130/5282506
/// Adapted by me.
///
/// Pass in the unique symbol and itll find the first and last index pairs
/// Can adapt to find all unique pairs at once.
/// </summary>
/// <param name="str">The string.</param>
/// <param name="searchstring">The searchstring letter (b, i, etc)</param>
/// <returns></returns>
public static IEnumerable<int> AllIndexesOf(string str, string searchstring)
{
//assumes the string is formatted correctly. Only one tag of the same type inside each tag.
int minIndex = str.IndexOf("["+searchstring+"]");
while (minIndex != -1)
{
Console.WriteLine("First: {0}", minIndex);
yield return minIndex;
var maxIndexEnd = str.IndexOf("[/"+ searchstring +"]", minIndex + searchstring.Length +3);//added three for the [/ and ] characters.
Console.WriteLine("End: {0}", maxIndexEnd);
if (maxIndexEnd == -1)
{
//Malformed string, no end element for a found start element
//Do something...
throw new FormatException("Malformed string");
}
yield return maxIndexEnd;
minIndex = str.IndexOf("[" + searchstring+"]", maxIndexEnd + searchstring.Length+2);//added two for the [ and ] characters
}
}
If you wish to make it an extension method for string change signature to this:
public static IEnumerable<int> AllIndexesOf(this string str, string searchstring)
Heres the console result for bold indexes:
Pair: 0 | 8
Pair: 33 | 45
I have not fully tested this method for all edge cases.
First, all my cities were returned as UPPERCASE, so I switched them to lowercase. How can I get the first letter as uppercase now? Thanks for any help!
List<string> cities = new List<string>();
foreach (DataRow row in dt.Rows)
{
cities.Add(row[0].ToString().ToLower());
**ADDED THIS BUT NOTHING HAPPENED**
CultureInfo.CurrentCulture.TextInfo.ToTitleCase(row[0] as string);
}
return cities;
Use the TextInfo.ToTitleCase method:
System.Globalization.TextInfo.ToTitleCase();
A bit from the MSDN example, modified to work with OP's code:
// Defines the string with mixed casing.
string myString = row[0] as String;
// Creates a TextInfo based on the "en-US" culture.
TextInfo myTI = new CultureInfo("en-US", false).TextInfo;
// Retrieve a titlecase'd version of the string.
string myCity = myTI.ToTitleCase(myString);
All in one line:
string myCity = new CultureInfo("en-US", false).TextInfo.ToTitleCase(row[0] as String);
I know I'm resurrecting a ghost here, but I had the same problem, and wanted to share what I think is the best solution. There are a few ways you can do it, either splitting the string and replacing the first letter, or transforming it into a char-array for better performance. The best performance, though, comes with using a regular expression.
You can use a bit of Regex voodoo to find the first letter of each word. The pattern you are looking for is \b\w (\b means the beginning of a word, and \w is an alpha character). Use a MatchEvaluator delegate (or an equivalent lambda expression) to modify the string (the first character, that your pattern found).
Here's an extension method over string that will upper-case-ify the first letter of each word in a string:
static string UpperCaseFirst(this string input)
{
return Regex.Replace(input, #"\b\w", (Match match)=> match.ToString().ToUpper())
}
Regex may seem a bit long, but works
List<string> cities = new List<string>();
foreach (DataRow row in dt.Rows)
{
string city = row[0].ToString();
cities.Add(String.Concat(Regex.Replace(city, "([a-zA-Z])([a-zA-Z]+)", "$1").ToUpper(System.Globalization.CultureInfo.InvariantCulture), Regex.Replace(city, "([a-zA-Z])([a-zA-Z]+)", "$2").ToLower(System.Globalization.CultureInfo.InvariantCulture)));
}
return cities;
new CultureInfo("en-US",false).TextInfo.ToTitleCase(myString);
here is an extension method that you can use. It supports the current culture, or allows you to pass in the culture.
to use:
cities.Add(row[0].ToString().ToTitleCase()
public static class StringExtension
{
/// <summary>
/// Use the current thread's culture info for conversion
/// </summary>
public static string ToTitleCase(this string str)
{
var cultureInfo = System.Threading.Thread.CurrentThread.CurrentCulture;
return cultureInfo.TextInfo.ToTitleCase(str.ToLower());
}
/// <summary>
/// Overload which uses the culture info with the specified name
/// </summary>
public static string ToTitleCase(this string str, string cultureInfoName)
{
var cultureInfo = new CultureInfo(cultureInfoName);
return cultureInfo.TextInfo.ToTitleCase(str.ToLower());
}
/// <summary>
/// Overload which uses the specified culture info
/// </summary>
public static string ToTitleCase(this string str, CultureInfo cultureInfo)
{
return cultureInfo.TextInfo.ToTitleCase(str.ToLower());
}
}
With linq:
String newString = new String(str.Select((ch, index) => (index == 0) ? ch : Char.ToLower(ch)).ToArray()); *
gently stolen from this post : How to lowercase a string except for first character with C#
You could use this method (or create an extension method out of it):
static string UpperCaseFirst(this string s)
{
// Check for empty string.
if (string.IsNullOrEmpty(s))
{
return string.Empty;
}
// Return char and concat substring.
return char.ToUpper(s[0]) + s.Substring(1);
}
Here's quick little method:
public string UpperCaseFirstLetter(string YourLowerCaseWord)
{
if (string.IsNullOrEmpty(YourLowerCaseWord))
return string.Empty;
return char.ToUpper(YourLowerCaseWord[0]) + YourLowerCaseWord.Substring(1);
}
public static string UppercaseFirst(string value)
{
// Check for empty string.
if (string.IsNullOrEmpty(value))
{
return string.Empty;
}
// Return char and concat substring.
return char.ToUpper(value[0]) + value.Substring(1);
}
cities.Select(UppercaseFirst).ToList();
I have implemented an algorithm that will generate unique names for files that will save on hard drive. I'm appending DateTime: Hours,Minutes,Second and Milliseconds but still it generates duplicate name of files because im uploading multiple files at a time.
What is the best solution to generate unique names for files to be stored on hard drive so no 2 files are same?
If readability doesn't matter, use GUIDs.
E.g.:
var myUniqueFileName = string.Format(#"{0}.txt", Guid.NewGuid());
or shorter:
var myUniqueFileName = $#"{Guid.NewGuid()}.txt";
In my programs, I sometimes try e.g. 10 times to generate a readable name ("Image1.png"…"Image10.png") and if that fails (because the file already exists), I fall back to GUIDs.
Update:
Recently, I've also use DateTime.Now.Ticks instead of GUIDs:
var myUniqueFileName = string.Format(#"{0}.txt", DateTime.Now.Ticks);
or
var myUniqueFileName = $#"{DateTime.Now.Ticks}.txt";
The benefit to me is that this generates a shorter and "nicer looking" filename, compared to GUIDs.
Please note that in some cases (e.g. when generating a lot of random names in a very short time), this might make non-unique values.
Stick to GUIDs if you want to make really sure that the file names are unique, even when transfering them to other computers.
Use
Path.GetTempFileName()
or use new GUID().
Path.GetTempFilename() on MSDN.
System.IO.Path.GetRandomFileName()
Path.GetRandomFileName() on MSDN.
If the readability of the file name isn't important, then the GUID, as suggested by many will do. However, I find that looking into a directory with 1000 GUID file names is very daunting to sort through. So I usually use a combination of a static string which gives the file name some context information, a timestamp, and GUID.
For example:
public string GenerateFileName(string context)
{
return context + "_" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + "_" + Guid.NewGuid().ToString("N");
}
filename1 = GenerateFileName("MeasurementData");
filename2 = GenerateFileName("Image");
This way, when I sort by filename, it will automatically group the files by the context string and sort by timestamp.
Note that the filename limit in windows is 255 characters.
Here's an algorithm that returns a unique readable filename based on the original supplied. If the original file exists, it incrementally tries to append an index to the filename until it finds one that doesn't exist. It reads the existing filenames into a HashSet to check for collisions so it's pretty quick (a few hundred filenames per second on my machine), it's thread safe too, and doesn't suffer from race conditions.
For example, if you pass it test.txt, it will attempt to create files in this order:
test.txt
test (2).txt
test (3).txt
etc. You can specify the maximum attempts or just leave it at the default.
Here's a complete example:
class Program
{
static FileStream CreateFileWithUniqueName(string folder, string fileName,
int maxAttempts = 1024)
{
// get filename base and extension
var fileBase = Path.GetFileNameWithoutExtension(fileName);
var ext = Path.GetExtension(fileName);
// build hash set of filenames for performance
var files = new HashSet<string>(Directory.GetFiles(folder));
for (var index = 0; index < maxAttempts; index++)
{
// first try with the original filename, else try incrementally adding an index
var name = (index == 0)
? fileName
: String.Format("{0} ({1}){2}", fileBase, index, ext);
// check if exists
var fullPath = Path.Combine(folder, name);
if(files.Contains(fullPath))
continue;
// try to create the file
try
{
return new FileStream(fullPath, FileMode.CreateNew, FileAccess.Write);
}
catch (DirectoryNotFoundException) { throw; }
catch (DriveNotFoundException) { throw; }
catch (IOException)
{
// Will occur if another thread created a file with this
// name since we created the HashSet. Ignore this and just
// try with the next filename.
}
}
throw new Exception("Could not create unique filename in " + maxAttempts + " attempts");
}
static void Main(string[] args)
{
for (var i = 0; i < 500; i++)
{
using (var stream = CreateFileWithUniqueName(#"c:\temp\", "test.txt"))
{
Console.WriteLine("Created \"" + stream.Name + "\"");
}
}
Console.ReadKey();
}
}
I use GetRandomFileName:
The GetRandomFileName method returns a cryptographically strong, random string that can be used as either a folder name or a file name. Unlike GetTempFileName, GetRandomFileName does not create a file. When the security of your file system is paramount, this method should be used instead of GetTempFileName.
Example:
public static string GenerateFileName(string extension="")
{
return string.Concat(Path.GetRandomFileName().Replace(".", ""),
(!string.IsNullOrEmpty(extension)) ? (extension.StartsWith(".") ? extension : string.Concat(".", extension)) : "");
}
You can have a unique file name automatically generated for you without any custom methods. Just use the following with the StorageFolder Class or the StorageFile Class. The key here is: CreationCollisionOption.GenerateUniqueName and NameCollisionOption.GenerateUniqueName
To create a new file with a unique filename:
var myFile = await ApplicationData.Current.LocalFolder.CreateFileAsync("myfile.txt", NameCollisionOption.GenerateUniqueName);
To copy a file to a location with a unique filename:
var myFile2 = await myFile1.CopyAsync(ApplicationData.Current.LocalFolder, myFile1.Name, NameCollisionOption.GenerateUniqueName);
To move a file with a unique filename in the destination location:
await myFile.MoveAsync(ApplicationData.Current.LocalFolder, myFile.Name, NameCollisionOption.GenerateUniqueName);
To rename a file with a unique filename in the destination location:
await myFile.RenameAsync(myFile.Name, NameCollisionOption.GenerateUniqueName);
Create your timestamped filename
following your normal process
Check to see if filename exists
False - save file
True - Append additional character to file, perhaps a counter
Go to step 2
Do you need the date time stamp in the filename?
You could make the filename a GUID.
I have been using the following code and its working fine. I hope this might help you.
I begin with a unique file name using a timestamp -
"context_" + DateTime.Now.ToString("yyyyMMddHHmmssffff")
C# code -
public static string CreateUniqueFile(string logFilePath, string logFileName, string fileExt)
{
try
{
int fileNumber = 1;
//prefix with . if not already provided
fileExt = (!fileExt.StartsWith(".")) ? "." + fileExt : fileExt;
//Generate new name
while (File.Exists(Path.Combine(logFilePath, logFileName + "-" + fileNumber.ToString() + fileExt)))
fileNumber++;
//Create empty file, retry until one is created
while (!CreateNewLogfile(logFilePath, logFileName + "-" + fileNumber.ToString() + fileExt))
fileNumber++;
return logFileName + "-" + fileNumber.ToString() + fileExt;
}
catch (Exception)
{
throw;
}
}
private static bool CreateNewLogfile(string logFilePath, string logFile)
{
try
{
FileStream fs = new FileStream(Path.Combine(logFilePath, logFile), FileMode.CreateNew);
fs.Close();
return true;
}
catch (IOException) //File exists, can not create new
{
return false;
}
catch (Exception) //Exception occured
{
throw;
}
}
Why can't we make a unique id as below.
We can use DateTime.Now.Ticks and Guid.NewGuid().ToString() to combine together and make a unique id.
As the DateTime.Now.Ticks is added, we can find out the Date and Time in seconds at which the unique id is created.
Please see the code.
var ticks = DateTime.Now.Ticks;
var guid = Guid.NewGuid().ToString();
var uniqueSessionId = ticks.ToString() +'-'+ guid; //guid created by combining ticks and guid
var datetime = new DateTime(ticks);//for checking purpose
var datetimenow = DateTime.Now; //both these date times are different.
We can even take the part of ticks in unique id and check for the date and time later for future reference.
You can attach the unique id created to the filename or can be used for creating unique session id for login-logout of users to our application or website.
How about using Guid.NewGuid() to create a GUID and use that as the filename (or part of the filename together with your time stamp if you like).
I've written a simple recursive function that generates file names like Windows does, by appending a sequence number prior to the file extension.
Given a desired file path of C:\MyDir\MyFile.txt, and the file already exists, it returns a final file path of C:\MyDir\MyFile_1.txt.
It is called like this:
var desiredPath = #"C:\MyDir\MyFile.txt";
var finalPath = UniqueFileName(desiredPath);
private static string UniqueFileName(string path, int count = 0)
{
if (count == 0)
{
if (!File.Exists(path))
{
return path;
}
}
else
{
var candidatePath = string.Format(
#"{0}\{1}_{2}{3}",
Path.GetDirectoryName(path),
Path.GetFileNameWithoutExtension(path),
count,
Path.GetExtension(path));
if (!File.Exists(candidatePath))
{
return candidatePath;
}
}
count++;
return UniqueFileName(path, count);
}
DateTime.Now.Ticks is not safe, Guid.NewGuid() is too ugly, if you need something clean and almost safe (it's not 100% safe for example if you call it 1,000,000 times in 1ms), try:
Math.Abs(Guid.NewGuid().GetHashCode())
By safe I mean safe to be unique when you call it so many times in very short period few ms of time.
If you would like to have the datetime,hours,minutes etc..you can use a static variable. Append the value of this variable to the filename. You can start the counter with 0 and increment when you have created a file. This way the filename will surely be unique since you have seconds also in the file.
I usually do something along these lines:
start with a stem file name (work.dat1 for instance)
try to create it with CreateNew
if that works, you've got the file, otherwise...
mix the current date/time into the filename (work.2011-01-15T112357.dat for instance)
try to create the file
if that worked, you've got the file, otherwise...
Mix a monotonic counter into the filename (work.2011-01-15T112357.0001.dat for instance. (I dislike GUIDs. I prefer order/predictability.)
try to create the file. Keep ticking up the counter and retrying until a file gets created for you.
Here's a sample class:
static class DirectoryInfoHelpers
{
public static FileStream CreateFileWithUniqueName( this DirectoryInfo dir , string rootName )
{
FileStream fs = dir.TryCreateFile( rootName ) ; // try the simple name first
// if that didn't work, try mixing in the date/time
if ( fs == null )
{
string date = DateTime.Now.ToString( "yyyy-MM-ddTHHmmss" ) ;
string stem = Path.GetFileNameWithoutExtension(rootName) ;
string ext = Path.GetExtension(rootName) ?? ".dat" ;
ext = ext.Substring(1);
string fn = string.Format( "{0}.{1}.{2}" , stem , date , ext ) ;
fs = dir.TryCreateFile( fn ) ;
// if mixing in the date/time didn't work, try a sequential search
if ( fs == null )
{
int seq = 0 ;
do
{
fn = string.Format( "{0}.{1}.{2:0000}.{3}" , stem , date , ++seq , ext ) ;
fs = dir.TryCreateFile( fn ) ;
} while ( fs == null ) ;
}
}
return fs ;
}
private static FileStream TryCreateFile(this DirectoryInfo dir , string fileName )
{
FileStream fs = null ;
try
{
string fqn = Path.Combine( dir.FullName , fileName ) ;
fs = new FileStream( fqn , FileMode.CreateNew , FileAccess.ReadWrite , FileShare.None ) ;
}
catch ( Exception )
{
fs = null ;
}
return fs ;
}
}
You might want to tweak the algorithm (always use all the possible components to the file name for instance). Depends on the context -- If I was creating log files for instance, that I might want to rotate out of existence, you'd want them all to share the same pattern to the name.
The code isn't perfect (no checks on the data passed in for instance). And the algorithm's not perfect (if you fill up the hard drive or encounter permissions, actual I/O errors or other file system errors, for instance, this will hang, as it stands, in an infinite loop).
I ends up concatenating GUID with Day Month Year Second Millisecond string and i think this solution is quite good in my scenario
you can use Random.Next() also to generate a random number. you can see the MSDN link: http://msdn.microsoft.com/en-us/library/9b3ta19y.aspx
I wrote a class specifically for doing this. It's initialized with a "base" part (defaults to a minute-accurate timestamp) and after that appends letters to make unique names. So, if the first stamp generated is 1907101215a, the second would be 1907101215b, then 1907101215c, et cetera.
If I need more than 25 unique stamps then I use unary 'z's to count 25's. So, it goes 1907101215y, 1907101215za, 1907101215zb, ... 1907101215zy, 1907101215zza, 1907101215zzb, and so forth. This guarantees that the stamps will always sort alphanumerically in the order they were generated (as long as the next character after the stamp isn't a letter).
It isn't thread-safe, doesn't automatically update the time, and quickly bloats if you need hundreds of stamps, but I find it sufficient for my needs.
/// <summary>
/// Class for generating unique stamps (for filenames, etc.)
/// </summary>
/// <remarks>
/// Each time ToString() is called, a unique stamp is generated.
/// Stamps are guaranteed to sort alphanumerically in order of generation.
/// </remarks>
public class StampGenerator
{
/// <summary>
/// All the characters which could be the last character in the stamp.
/// </summary>
private static readonly char[] _trailingChars =
{
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
'u', 'v', 'w', 'x', 'y'
};
/// <summary>
/// How many valid trailing characters there are.
/// </summary>
/// <remarks>Should always equal _trailingChars.Length</remarks>
public const int TRAILING_RANGE = 25;
/// <summary>
/// Maximum length of the stamp. Hard-coded for laziness.
/// </summary>
public const int MAX_LENGTH_STAMP = 28;
/// <summary>
/// Base portion of the stamp. Will be constant between calls.
/// </summary>
/// <remarks>
/// This is intended to uniquely distinguish between instances.
/// Default behavior is to generate a minute-accurate timestamp.
/// </remarks>
public string StampBase { get; }
/// <summary>
/// Number of times this instance has been called.
/// </summary>
public int CalledTimes { get; private set; }
/// <summary>
/// Maximum number of stamps that can be generated with a given base.
/// </summary>
public int MaxCalls { get; }
/// <summary>
/// Number of stamps remaining for this instance.
/// </summary>
public int RemainingCalls { get { return MaxCalls - CalledTimes; } }
/// <summary>
/// Instantiate a StampGenerator with a specific base.
/// </summary>
/// <param name="stampBase">Base of stamp.</param>
/// <param name="calledTimes">
/// Number of times this base has already been used.
/// </param>
public StampGenerator(string stampBase, int calledTimes = 0)
{
if (stampBase == null)
{
throw new ArgumentNullException("stampBase");
}
else if (Regex.IsMatch(stampBase, "[^a-zA-Z_0-9 \\-]"))
{
throw new ArgumentException("Invalid characters in Stamp Base.",
"stampBase");
}
else if (stampBase.Length >= MAX_LENGTH_STAMP - 1)
{
throw new ArgumentException(
string.Format("Stamp Base too long. (Length {0} out of {1})",
stampBase.Length, MAX_LENGTH_STAMP - 1), "stampBase");
}
else if (calledTimes < 0)
{
throw new ArgumentOutOfRangeException(
"calledTimes", calledTimes, "calledTimes cannot be negative.");
}
else
{
int maxCalls = TRAILING_RANGE * (MAX_LENGTH_STAMP - stampBase.Length);
if (calledTimes >= maxCalls)
{
throw new ArgumentOutOfRangeException(
"calledTimes", calledTimes, string.Format(
"Called Times too large; max for stem of length {0} is {1}.",
stampBase.Length, maxCalls));
}
else
{
StampBase = stampBase;
CalledTimes = calledTimes;
MaxCalls = maxCalls;
}
}
}
/// <summary>
/// Instantiate a StampGenerator with default base string based on time.
/// </summary>
public StampGenerator() : this(DateTime.Now.ToString("yMMddHHmm")) { }
/// <summary>
/// Generate a unique stamp.
/// </summary>
/// <remarks>
/// Stamp values are orered like this:
/// a, b, ... x, y, za, zb, ... zx, zy, zza, zzb, ...
/// </remarks>
/// <returns>A unique stamp.</returns>
public override string ToString()
{
int zCount = CalledTimes / TRAILING_RANGE;
int trailing = CalledTimes % TRAILING_RANGE;
int length = StampBase.Length + zCount + 1;
if (length > MAX_LENGTH_STAMP)
{
throw new InvalidOperationException(
"Stamp length overflown! Cannot generate new stamps.");
}
else
{
CalledTimes = CalledTimes + 1;
var builder = new StringBuilder(StampBase, length);
builder.Append('z', zCount);
builder.Append(_trailingChars[trailing]);
return builder.ToString();
}
}
}
Old question, I know, but here's is what works for me. If multiple threads download files, assign each a unique number and prepend to it the filename, e.g. 01_202107210938xxxx
If you're wanting to generate a file name based off of some text like a DateTime and maybe a GUID, I have made NuGet package that allows you to do this, if you count the amount of filenames you can use that as the seed so that it is truly random. I tried to make it as straight forward and as easy to use as possible, but here's some code that you can use to generate it:
First install the NuGet package https://www.nuget.org/packages/uniqueit/
Then import it.
Finally, enter the code below:
List<string> list = new List<string>();
list.Add(new DateTime().ToString());
list.Add("Some filename or GUID");
int amountoffiles = 5000;
string final_filename = vuniqueit.Identity.GenerateUUID(list, amountoffiles));
Is there any way to format a string by name rather than position in C#?
In python, I can do something like this example (shamelessly stolen from here):
>>> print '%(language)s has %(#)03d quote types.' % \
{'language': "Python", "#": 2}
Python has 002 quote types.
Is there any way to do this in C#? Say for instance:
String.Format("{some_variable}: {some_other_variable}", ...);
Being able to do this using a variable name would be nice, but a dictionary is acceptable too.
There is no built-in method for handling this.
Here's one method
string myString = "{foo} is {bar} and {yadi} is {yada}".Inject(o);
Here's another
Status.Text = "{UserName} last logged in at {LastLoginDate}".FormatWith(user);
A third improved method partially based on the two above, from Phil Haack
Update: This is now built-in as of C# 6 (released in 2015).
String Interpolation
$"{some_variable}: {some_other_variable}"
I have an implementation I just posted to my blog here: http://haacked.com/archive/2009/01/04/fun-with-named-formats-string-parsing-and-edge-cases.aspx
It addresses some issues that these other implementations have with brace escaping. The post has details. It does the DataBinder.Eval thing too, but is still very fast.
Interpolated strings were added into C# 6.0 and Visual Basic 14
Both were introduced through new Roslyn compiler in Visual Studio 2015.
C# 6.0:
return "\{someVariable} and also \{someOtherVariable}" OR
return $"{someVariable} and also {someOtherVariable}"
source: what's new in C#6.0
VB 14:
return $"{someVariable} and also {someOtherVariable}"
source: what's new in VB 14
Noteworthy features (in Visual Studio 2015 IDE):
syntax coloring is supported - variables contained in strings are highlighted
refactoring is supported - when renaming, variables contained in strings get renamed, too
actually not only variable names, but expressions are supported - e.g. not only {index} works, but also {(index + 1).ToString().Trim()}
Enjoy! (& click "Send a Smile" in the VS)
You can also use anonymous types like this:
public string Format(string input, object p)
{
foreach (PropertyDescriptor prop in TypeDescriptor.GetProperties(p))
input = input.Replace("{" + prop.Name + "}", (prop.GetValue(p) ?? "(null)").ToString());
return input;
}
Of course it would require more code if you also want to parse formatting, but you can format a string using this function like:
Format("test {first} and {another}", new { first = "something", another = "something else" })
There doesn't appear to be a way to do this out of the box. Though, it looks feasible to implement your own IFormatProvider that links to an IDictionary for values.
var Stuff = new Dictionary<string, object> {
{ "language", "Python" },
{ "#", 2 }
};
var Formatter = new DictionaryFormatProvider();
// Interpret {0:x} where {0}=IDictionary and "x" is hash key
Console.WriteLine string.Format(Formatter, "{0:language} has {0:#} quote types", Stuff);
Outputs:
Python has 2 quote types
The caveat is that you can't mix FormatProviders, so the fancy text formatting can't be used at the same time.
The framework itself does not provide a way to do this, but you can take a look at this post by Scott Hanselman. Example usage:
Person p = new Person();
string foo = p.ToString("{Money:C} {LastName}, {ScottName} {BirthDate}");
Assert.AreEqual("$3.43 Hanselman, {ScottName} 1/22/1974 12:00:00 AM", foo);
This code by James Newton-King is similar and works with sub-properties and indexes,
string foo = "Top result for {Name} was {Results[0].Name}".FormatWith(student));
James's code relies on System.Web.UI.DataBinder to parse the string and requires referencing System.Web, which some people don't like to do in non-web applications.
EDIT: Oh and they work nicely with anonymous types, if you don't have an object with properties ready for it:
string name = ...;
DateTime date = ...;
string foo = "{Name} - {Birthday}".FormatWith(new { Name = name, Birthday = date });
See https://stackoverflow.com/questions/271398?page=2#358259
With the linked-to extension you can write this:
var str = "{foo} {bar} {baz}".Format(foo=>"foo", bar=>2, baz=>new object());
and you'll get "foo 2 System.Object".
I think the closest you'll get is an indexed format:
String.Format("{0} has {1} quote types.", "C#", "1");
There's also String.Replace(), if you're willing to do it in multiple steps and take it on faith that you won't find your 'variables' anywhere else in the string:
string MyString = "{language} has {n} quote types.";
MyString = MyString.Replace("{language}", "C#").Replace("{n}", "1");
Expanding this to use a List:
List<KeyValuePair<string, string>> replacements = GetFormatDictionary();
foreach (KeyValuePair<string, string> item in replacements)
{
MyString = MyString.Replace(item.Key, item.Value);
}
You could do that with a Dictionary<string, string> too by iterating it's .Keys collections, but by using a List<KeyValuePair<string, string>> we can take advantage of the List's .ForEach() method and condense it back to a one-liner:
replacements.ForEach(delegate(KeyValuePair<string,string>) item) { MyString = MyString.Replace(item.Key, item.Value);});
A lambda would be even simpler, but I'm still on .Net 2.0. Also note that the .Replace() performance isn't stellar when used iteratively, since strings in .Net are immutable. Also, this requires the MyString variable be defined in such a way that it's accessible to the delegate, so it's not perfect yet.
My open source library, Regextra, supports named formatting (amongst other things). It currently targets .NET 4.0+ and is available on NuGet. I also have an introductory blog post about it: Regextra: helping you reduce your (problems){2}.
The named formatting bit supports:
Basic formatting
Nested properties formatting
Dictionary formatting
Escaping of delimiters
Standard/Custom/IFormatProvider string formatting
Example:
var order = new
{
Description = "Widget",
OrderDate = DateTime.Now,
Details = new
{
UnitPrice = 1500
}
};
string template = "We just shipped your order of '{Description}', placed on {OrderDate:d}. Your {{credit}} card will be billed {Details.UnitPrice:C}.";
string result = Template.Format(template, order);
// or use the extension: template.FormatTemplate(order);
Result:
We just shipped your order of 'Widget', placed on 2/28/2014. Your {credit} card will be billed $1,500.00.
Check out the project's GitHub link (above) and wiki for other examples.
private static Regex s_NamedFormatRegex = new Regex(#"\{(?!\{)(?<key>[\w]+)(:(?<fmt>(\{\{|\}\}|[^\{\}])*)?)?\}", RegexOptions.Compiled);
public static StringBuilder AppendNamedFormat(this StringBuilder builder,IFormatProvider provider, string format, IDictionary<string, object> args)
{
if (builder == null) throw new ArgumentNullException("builder");
var str = s_NamedFormatRegex.Replace(format, (mt) => {
string key = mt.Groups["key"].Value;
string fmt = mt.Groups["fmt"].Value;
object value = null;
if (args.TryGetValue(key,out value)) {
return string.Format(provider, "{0:" + fmt + "}", value);
} else {
return mt.Value;
}
});
builder.Append(str);
return builder;
}
public static StringBuilder AppendNamedFormat(this StringBuilder builder, string format, IDictionary<string, object> args)
{
if (builder == null) throw new ArgumentNullException("builder");
return builder.AppendNamedFormat(null, format, args);
}
Example:
var builder = new StringBuilder();
builder.AppendNamedFormat(
#"你好,{Name},今天是{Date:yyyy/MM/dd}, 这是你第{LoginTimes}次登录，积分{Score:{{ 0.00 }}}",
new Dictionary<string, object>() {
{ "Name", "wayjet" },
{ "LoginTimes",18 },
{ "Score", 100.4 },
{ "Date",DateTime.Now }
});
Output:
你好,wayjet,今天是2011-05-04, 这是你第18次登录，积分{ 100.40 }
Check this one:
public static string StringFormat(string format, object source)
{
var matches = Regex.Matches(format, #"\{(.+?)\}");
List<string> keys = (from Match matche in matches select matche.Groups[1].Value).ToList();
return keys.Aggregate(
format,
(current, key) =>
{
int colonIndex = key.IndexOf(':');
return current.Replace(
"{" + key + "}",
colonIndex > 0
? DataBinder.Eval(source, key.Substring(0, colonIndex), "{0:" + key.Substring(colonIndex + 1) + "}")
: DataBinder.Eval(source, key).ToString());
});
}
Sample:
string format = "{foo} is a {bar} is a {baz} is a {qux:#.#} is a really big {fizzle}";
var o = new { foo = 123, bar = true, baz = "this is a test", qux = 123.45, fizzle = DateTime.Now };
Console.WriteLine(StringFormat(format, o));
Performance is pretty ok compared to other solutions.
I doubt this will be possible. The first thing that comes to mind is how are you going to get access to local variable names?
There might be some clever way using LINQ and Lambda expressions to do this however.
Here's one I made a while back. It extends String with a Format method taking a single argument. The nice thing is that it'll use the standard string.Format if you provide a simple argument like an int, but if you use something like anonymous type it'll work too.
Example usage:
"The {Name} family has {Children} children".Format(new { Children = 4, Name = "Smith" })
Would result in "The Smith family has 4 children."
It doesn't do crazy binding stuff like arrays and indexers. But it is super simple and high performance.
public static class AdvancedFormatString
{
/// <summary>
/// An advanced version of string.Format. If you pass a primitive object (string, int, etc), it acts like the regular string.Format. If you pass an anonmymous type, you can name the paramters by property name.
/// </summary>
/// <param name="formatString"></param>
/// <param name="arg"></param>
/// <returns></returns>
/// <example>
/// "The {Name} family has {Children} children".Format(new { Children = 4, Name = "Smith" })
///
/// results in
/// "This Smith family has 4 children
/// </example>
public static string Format(this string formatString, object arg, IFormatProvider format = null)
{
if (arg == null)
return formatString;
var type = arg.GetType();
if (Type.GetTypeCode(type) != TypeCode.Object || type.IsPrimitive)
return string.Format(format, formatString, arg);
var properties = TypeDescriptor.GetProperties(arg);
return formatString.Format((property) =>
{
var value = properties[property].GetValue(arg);
return Convert.ToString(value, format);
});
}
public static string Format(this string formatString, Func<string, string> formatFragmentHandler)
{
if (string.IsNullOrEmpty(formatString))
return formatString;
Fragment[] fragments = GetParsedFragments(formatString);
if (fragments == null || fragments.Length == 0)
return formatString;
return string.Join(string.Empty, fragments.Select(fragment =>
{
if (fragment.Type == FragmentType.Literal)
return fragment.Value;
else
return formatFragmentHandler(fragment.Value);
}).ToArray());
}
private static Fragment[] GetParsedFragments(string formatString)
{
Fragment[] fragments;
if ( parsedStrings.TryGetValue(formatString, out fragments) )
{
return fragments;
}
lock (parsedStringsLock)
{
if ( !parsedStrings.TryGetValue(formatString, out fragments) )
{
fragments = Parse(formatString);
parsedStrings.Add(formatString, fragments);
}
}
return fragments;
}
private static Object parsedStringsLock = new Object();
private static Dictionary<string,Fragment[]> parsedStrings = new Dictionary<string,Fragment[]>(StringComparer.Ordinal);
const char OpeningDelimiter = '{';
const char ClosingDelimiter = '}';
/// <summary>
/// Parses the given format string into a list of fragments.
/// </summary>
/// <param name="format"></param>
/// <returns></returns>
static Fragment[] Parse(string format)
{
int lastCharIndex = format.Length - 1;
int currFragEndIndex;
Fragment currFrag = ParseFragment(format, 0, out currFragEndIndex);
if (currFragEndIndex == lastCharIndex)
{
return new Fragment[] { currFrag };
}
List<Fragment> fragments = new List<Fragment>();
while (true)
{
fragments.Add(currFrag);
if (currFragEndIndex == lastCharIndex)
{
break;
}
currFrag = ParseFragment(format, currFragEndIndex + 1, out currFragEndIndex);
}
return fragments.ToArray();
}
/// <summary>
/// Finds the next delimiter from the starting index.
/// </summary>
static Fragment ParseFragment(string format, int startIndex, out int fragmentEndIndex)
{
bool foundEscapedDelimiter = false;
FragmentType type = FragmentType.Literal;
int numChars = format.Length;
for (int i = startIndex; i < numChars; i++)
{
char currChar = format[i];
bool isOpenBrace = currChar == OpeningDelimiter;
bool isCloseBrace = isOpenBrace ? false : currChar == ClosingDelimiter;
if (!isOpenBrace && !isCloseBrace)
{
continue;
}
else if (i < (numChars - 1) && format[i + 1] == currChar)
{//{{ or }}
i++;
foundEscapedDelimiter = true;
}
else if (isOpenBrace)
{
if (i == startIndex)
{
type = FragmentType.FormatItem;
}
else
{
if (type == FragmentType.FormatItem)
throw new FormatException("Two consequtive unescaped { format item openers were found. Either close the first or escape any literals with another {.");
//curr character is the opening of a new format item. so we close this literal out
string literal = format.Substring(startIndex, i - startIndex);
if (foundEscapedDelimiter)
literal = ReplaceEscapes(literal);
fragmentEndIndex = i - 1;
return new Fragment(FragmentType.Literal, literal);
}
}
else
{//close bracket
if (i == startIndex || type == FragmentType.Literal)
throw new FormatException("A } closing brace existed without an opening { brace.");
string formatItem = format.Substring(startIndex + 1, i - startIndex - 1);
if (foundEscapedDelimiter)
formatItem = ReplaceEscapes(formatItem);//a format item with a { or } in its name is crazy but it could be done
fragmentEndIndex = i;
return new Fragment(FragmentType.FormatItem, formatItem);
}
}
if (type == FragmentType.FormatItem)
throw new FormatException("A format item was opened with { but was never closed.");
fragmentEndIndex = numChars - 1;
string literalValue = format.Substring(startIndex);
if (foundEscapedDelimiter)
literalValue = ReplaceEscapes(literalValue);
return new Fragment(FragmentType.Literal, literalValue);
}
/// <summary>
/// Replaces escaped brackets, turning '{{' and '}}' into '{' and '}', respectively.
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
static string ReplaceEscapes(string value)
{
return value.Replace("{{", "{").Replace("}}", "}");
}
private enum FragmentType
{
Literal,
FormatItem
}
private class Fragment
{
public Fragment(FragmentType type, string value)
{
Type = type;
Value = value;
}
public FragmentType Type
{
get;
private set;
}
/// <summary>
/// The literal value, or the name of the fragment, depending on fragment type.
/// </summary>
public string Value
{
get;
private set;
}
}
}
here is a simple method for any object:
using System.Text.RegularExpressions;
using System.ComponentModel;
public static string StringWithFormat(string format, object args)
{
Regex r = new Regex(#"\{([A-Za-z0-9_]+)\}");
MatchCollection m = r.Matches(format);
var properties = TypeDescriptor.GetProperties(args);
foreach (Match item in m)
{
try
{
string propertyName = item.Groups[1].Value;
format = format.Replace(item.Value, properties[propertyName].GetValue(args).ToString());
}
catch
{
throw new FormatException("The format string is not valid");
}
}
return format;
}
And here how to use it:
DateTime date = DateTime.Now;
string dateString = StringWithFormat("{Month}/{Day}/{Year}", date);
output : 2/27/2012
I implemented this is a simple class that duplicates the functionality of String.Format (except for when using classes). You can either use a dictionary or a type to define fields.
https://github.com/SergueiFedorov/NamedFormatString
C# 6.0 is adding this functionality right into the language spec, so NamedFormatString is for backwards compatibility.
I solved this in a slightly different way to the existing solutions.
It does the core of the named item replacement (not the reflection bit that some have done). It is extremely fast and simple...
This is my solution:
/// <summary>
/// Formats a string with named format items given a template dictionary of the items values to use.
/// </summary>
public class StringTemplateFormatter
{
private readonly IFormatProvider _formatProvider;
/// <summary>
/// Constructs the formatter with the specified <see cref="IFormatProvider"/>.
/// This is defaulted to <see cref="CultureInfo.CurrentCulture">CultureInfo.CurrentCulture</see> if none is provided.
/// </summary>
/// <param name="formatProvider"></param>
public StringTemplateFormatter(IFormatProvider formatProvider = null)
{
_formatProvider = formatProvider ?? CultureInfo.CurrentCulture;
}
/// <summary>
/// Formats a string with named format items given a template dictionary of the items values to use.
/// </summary>
/// <param name="text">The text template</param>
/// <param name="templateValues">The named values to use as replacements in the formatted string.</param>
/// <returns>The resultant text string with the template values replaced.</returns>
public string FormatTemplate(string text, Dictionary<string, object> templateValues)
{
var formattableString = text;
var values = new List<object>();
foreach (KeyValuePair<string, object> value in templateValues)
{
var index = values.Count;
formattableString = ReplaceFormattableItem(formattableString, value.Key, index);
values.Add(value.Value);
}
return String.Format(_formatProvider, formattableString, values.ToArray());
}
/// <summary>
/// Convert named string template item to numbered string template item that can be accepted by <see cref="string.Format(string,object[])">String.Format</see>
/// </summary>
/// <param name="formattableString">The string containing the named format item</param>
/// <param name="itemName">The name of the format item</param>
/// <param name="index">The index to use for the item value</param>
/// <returns>The formattable string with the named item substituted with the numbered format item.</returns>
private static string ReplaceFormattableItem(string formattableString, string itemName, int index)
{
return formattableString
.Replace("{" + itemName + "}", "{" + index + "}")
.Replace("{" + itemName + ",", "{" + index + ",")
.Replace("{" + itemName + ":", "{" + index + ":");
}
}
It is used in the following way:
[Test]
public void FormatTemplate_GivenANamedGuid_FormattedWithB_ShouldFormatCorrectly()
{
// Arrange
var template = "My guid {MyGuid:B} is awesome!";
var templateValues = new Dictionary<string, object> { { "MyGuid", new Guid("{A4D2A7F1-421C-4A1D-9CB2-9C2E70B05E19}") } };
var sut = new StringTemplateFormatter();
// Act
var result = sut.FormatTemplate(template, templateValues);
//Assert
Assert.That(result, Is.EqualTo("My guid {a4d2a7f1-421c-4a1d-9cb2-9c2e70b05e19} is awesome!"));
}
Hope someone finds this useful!
Even though the accepted answer gives some good examples, the .Inject as well as some of the Haack examples do not handle escaping. Many also rely heavily on Regex (slower), or DataBinder.Eval which is not available on .NET Core, and in some other environments.
With that in mind, I've written a simple state machine based parser that streams through characters, writing to a StringBuilder output, character by character. It is implemented as String extension method(s) and can take both a Dictionary<string, object> or object with parameters as input (using reflection).
It handles unlimited levels of {{{escaping}}} and throws FormatException when input contains unbalanced braces and/or other errors.
public static class StringExtension {
/// <summary>
/// Extension method that replaces keys in a string with the values of matching object properties.
/// </summary>
/// <param name="formatString">The format string, containing keys like {foo} and {foo:SomeFormat}.</param>
/// <param name="injectionObject">The object whose properties should be injected in the string</param>
/// <returns>A version of the formatString string with keys replaced by (formatted) key values.</returns>
public static string FormatWith(this string formatString, object injectionObject) {
return formatString.FormatWith(GetPropertiesDictionary(injectionObject));
}
/// <summary>
/// Extension method that replaces keys in a string with the values of matching dictionary entries.
/// </summary>
/// <param name="formatString">The format string, containing keys like {foo} and {foo:SomeFormat}.</param>
/// <param name="dictionary">An <see cref="IDictionary"/> with keys and values to inject into the string</param>
/// <returns>A version of the formatString string with dictionary keys replaced by (formatted) key values.</returns>
public static string FormatWith(this string formatString, IDictionary<string, object> dictionary) {
char openBraceChar = '{';
char closeBraceChar = '}';
return FormatWith(formatString, dictionary, openBraceChar, closeBraceChar);
}
/// <summary>
/// Extension method that replaces keys in a string with the values of matching dictionary entries.
/// </summary>
/// <param name="formatString">The format string, containing keys like {foo} and {foo:SomeFormat}.</param>
/// <param name="dictionary">An <see cref="IDictionary"/> with keys and values to inject into the string</param>
/// <returns>A version of the formatString string with dictionary keys replaced by (formatted) key values.</returns>
public static string FormatWith(this string formatString, IDictionary<string, object> dictionary, char openBraceChar, char closeBraceChar) {
string result = formatString;
if (dictionary == null || formatString == null)
return result;
// start the state machine!
// ballpark output string as two times the length of the input string for performance (avoids reallocating the buffer as often).
StringBuilder outputString = new StringBuilder(formatString.Length * 2);
StringBuilder currentKey = new StringBuilder();
bool insideBraces = false;
int index = 0;
while (index < formatString.Length) {
if (!insideBraces) {
// currently not inside a pair of braces in the format string
if (formatString[index] == openBraceChar) {
// check if the brace is escaped
if (index < formatString.Length - 1 && formatString[index + 1] == openBraceChar) {
// add a brace to the output string
outputString.Append(openBraceChar);
// skip over braces
index += 2;
continue;
}
else {
// not an escaped brace, set state to inside brace
insideBraces = true;
index++;
continue;
}
}
else if (formatString[index] == closeBraceChar) {
// handle case where closing brace is encountered outside braces
if (index < formatString.Length - 1 && formatString[index + 1] == closeBraceChar) {
// this is an escaped closing brace, this is okay
// add a closing brace to the output string
outputString.Append(closeBraceChar);
// skip over braces
index += 2;
continue;
}
else {
// this is an unescaped closing brace outside of braces.
// throw a format exception
throw new FormatException($"Unmatched closing brace at position {index}");
}
}
else {
// the character has no special meaning, add it to the output string
outputString.Append(formatString[index]);
// move onto next character
index++;
continue;
}
}
else {
// currently inside a pair of braces in the format string
// found an opening brace
if (formatString[index] == openBraceChar) {
// check if the brace is escaped
if (index < formatString.Length - 1 && formatString[index + 1] == openBraceChar) {
// there are escaped braces within the key
// this is illegal, throw a format exception
throw new FormatException($"Illegal escaped opening braces within a parameter - index: {index}");
}
else {
// not an escaped brace, we have an unexpected opening brace within a pair of braces
throw new FormatException($"Unexpected opening brace inside a parameter - index: {index}");
}
}
else if (formatString[index] == closeBraceChar) {
// handle case where closing brace is encountered inside braces
// don't attempt to check for escaped braces here - always assume the first brace closes the braces
// since we cannot have escaped braces within parameters.
// set the state to be outside of any braces
insideBraces = false;
// jump over brace
index++;
// at this stage, a key is stored in current key that represents the text between the two braces
// do a lookup on this key
string key = currentKey.ToString();
// clear the stringbuilder for the key
currentKey.Clear();
object outObject;
if (!dictionary.TryGetValue(key, out outObject)) {
// the key was not found as a possible replacement, throw exception
throw new FormatException($"The parameter \"{key}\" was not present in the lookup dictionary");
}
// we now have the replacement value, add the value to the output string
outputString.Append(outObject);
// jump to next state
continue;
} // if }
else {
// character has no special meaning, add it to the current key
currentKey.Append(formatString[index]);
// move onto next character
index++;
continue;
} // else
} // if inside brace
} // while
// after the loop, if all braces were balanced, we should be outside all braces
// if we're not, the input string was misformatted.
if (insideBraces) {
throw new FormatException("The format string ended before the parameter was closed.");
}
return outputString.ToString();
}
/// <summary>
/// Creates a Dictionary from an objects properties, with the Key being the property's
/// name and the Value being the properties value (of type object)
/// </summary>
/// <param name="properties">An object who's properties will be used</param>
/// <returns>A <see cref="Dictionary"/> of property values </returns>
private static Dictionary<string, object> GetPropertiesDictionary(object properties) {
Dictionary<string, object> values = null;
if (properties != null) {
values = new Dictionary<string, object>();
PropertyDescriptorCollection props = TypeDescriptor.GetProperties(properties);
foreach (PropertyDescriptor prop in props) {
values.Add(prop.Name, prop.GetValue(properties));
}
}
return values;
}
}
Ultimately, all the logic boils down into 10 main states - For when the state machine is outside a bracket and likewise inside a bracket, the next character is either an open brace, an escaped open brace, a closed brace, an escaped closed brace, or an ordinary character. Each of these conditions is handled individually as the loop progresses, adding characters to either an output StringBuffer or a key StringBuffer. When a parameter is closed, the value of the key StringBuffer is used to look up the parameter's value in the dictionary, which then gets pushed into the output StringBuffer. At the end, the value of the output StringBuffer is returned.
string language = "Python";
int numquotes = 2;
string output = language + " has "+ numquotes + " language types.";
Edit:
What I should have said was, "No, I don't believe what you want to do is supported by C#. This is as close as you are going to get."