I been having trouble trying to figure this out. When I think I have it I get told no. Here is a picture of it.
I am working on the save button. Now after the user adds the first name, last name and job title they can save it. If a user loads the file and it comes up in the listbox, that person should be able to click on the name and then hit the edit button and they should be able to edit it. I have code, but I did get inform it looked wackey and the string should have the first name, last name and job title.
It is getting me really confused as I am learning C#. I know how to use savefiledialog but I am not allowed to use it on this one. Here is what I am suppose to be doing:
When the user clicks the “Save” button, write the selected record to
the file specified in txtFilePath (absolute path not relative) without
truncating the values currently inside.
I am still working on my code since I got told that it will be better file writes records in a group of three strings. But this is the code I have right now.
private void Save_Click(object sender, EventArgs e)
{
string path = txtFilePath.Text;
if (File.Exists(path))
{
using (StreamWriter sw = File.CreateText(path))
{
foreach (Employee employee in employeeList.Items)
sw.WriteLine(employee);
}
}
else
try
{
StreamWriter sw = File.AppendText(path);
foreach (var item in employeeList.Items)
sw.WriteLine(item.ToString());
}
catch
{
MessageBox.Show("Please enter something in");
}
Now I can not use save or open file dialog. The user should be able to open any file on the C,E,F drive or where it is. I was also told it should be obj.Also the program should handle and exceptions that arise.
I know this might be a noobie question but my mind is stuck as I am still learning how to code with C#. Now I have been searching and reading. But I am not finding something to help me understand how to have all this into 1 code. If someone might be able to help or even point to a better web site I would appreciate it.
There are many, many ways to store data in a file. This code demonstrates 4 methods that are pretty easy to use. But the point is that you should probably be splitting up your data into separate pieces rather than storing them as one long string.
public class MyPublicData
{
public int id;
public string value;
}
[Serializable()]
class MyEncapsulatedData
{
private DateTime created;
private int length;
public MyEncapsulatedData(int length)
{
created = DateTime.Now;
this.length = length;
}
public DateTime ExpirationDate
{
get { return created.AddDays(length); }
}
}
class Program
{
static void Main(string[] args)
{
string testpath = System.IO.Path.Combine(
Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "TestFile");
// Method 1: Automatic XML serialization
// Requires that the type being serialized and all its serializable members are public
System.Xml.Serialization.XmlSerializer xs =
new System.Xml.Serialization.XmlSerializer(typeof(MyPublicData));
MyPublicData o1 = new MyPublicData() {id = 3141, value = "a test object"};
MyEncapsulatedData o2 = new MyEncapsulatedData(7);
using (System.IO.StreamWriter w = new System.IO.StreamWriter(testpath + ".xml"))
{
xs.Serialize(w, o1);
}
// Method 2: Manual XML serialization
System.Xml.XmlWriter xw = System.Xml.XmlWriter.Create(testpath + "1.xml");
xw.WriteStartElement("MyPublicData");
xw.WriteStartAttribute("id");
xw.WriteValue(o1.id);
xw.WriteEndAttribute();
xw.WriteAttributeString("value", o1.value);
xw.WriteEndElement();
xw.Close();
// Method 3: Automatic binary serialization
// Requires that the type being serialized be marked with the "Serializable" attribute
using (System.IO.FileStream f = new System.IO.FileStream(testpath + ".bin", System.IO.FileMode.Create))
{
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bf =
new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
bf.Serialize(f, o2);
}
// Demonstrate how automatic binary deserialization works
// and prove that it handles objects with private members
using (System.IO.FileStream f = new System.IO.FileStream(testpath + ".bin", System.IO.FileMode.Open))
{
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bf =
new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
MyEncapsulatedData o3 = (MyEncapsulatedData)bf.Deserialize(f);
Console.WriteLine(o3.ExpirationDate.ToString());
}
// Method 4: Manual binary serialization
using (System.IO.FileStream f = new System.IO.FileStream(testpath + "1.bin", System.IO.FileMode.Create))
{
using (System.IO.BinaryWriter w = new System.IO.BinaryWriter(f))
{
w.Write(o1.id);
w.Write(o1.value);
}
}
// Demonstrate how manual binary deserialization works
using (System.IO.FileStream f = new System.IO.FileStream(testpath + "1.bin", System.IO.FileMode.Open))
{
using (System.IO.BinaryReader r = new System.IO.BinaryReader(f))
{
MyPublicData o4 = new MyPublicData() { id = r.ReadInt32(), value = r.ReadString() };
Console.WriteLine("{0}: {1}", o4.id, o4.value);
}
}
}
}
As you are writing the employee objects with WriteLine, the underlying ToString() is being invoked. What you have to do first is to customize that ToString() methods to fit your needs, in this way:
public class Employee
{
public string FirstName;
public string LastName;
public string JobTitle;
// all other declarations here
...........
// Override ToString()
public override string ToString()
{
return string.Format("'{0}', '{1}', '{2}'", this.FirstName, this.LastName, this.JobTitle);
}
}
This way, your writing code still keeps clean and readable.
By the way, there is not a reverse equivalent of ToSTring, but to follow .Net standards, I suggest you to implement an Employee's method like:
public static Employee Parse(string)
{
// your code here, return a new Employee object
}
You have to determine a way of saving that suits your needs. A simple way to store this info could be CSV:
"Firstname1","Lastname 1", "Jobtitle1"
" Firstname2", "Lastname2","Jobtitle2 "
As you can see, data won't be truncated, since the delimiter " is used to determine string boundaries.
As shown in this question, using CsvHelper might be an option. But given this is homework and the constraints therein, you might have to create this method yourself. You could put this in Employee (or make it override ToString()) that does something along those lines:
public String GetAsCSV(String firstName, String lastName, String jobTitle)
{
return String.Format("\"{0}\",\"{1}\",\"{2}\"", firstName, lastName, jobTitle);
}
I'll leave the way how to read the data back in as an exercise to you. ;-)
Related
My professor doesn't want all my code in one class. I am new to C# as well so I don't know how to make my code cohesive and have it abstract away any of the implementation details. Here is my code I have so far. I am trying to make multiple classes because this class has too many responsibilities and I don't know how to do that.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
namespace SvgGenerator
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Please enter the name of the output file.");
string outputFile = Console.ReadLine() + ".svg";
Console.WriteLine("Do you want to manually enter the squares or read them from a file? Man or File?");
string fileRead = Console.ReadLine();
if (fileRead.Trim() == "Manually" || fileRead.Trim() == "manually" || fileRead.Trim() == "Man" || fileRead.Trim() == "man")
{
ManInput(outputFile);
}
if (fileRead.Trim() == "file" || fileRead.Trim() == "File")
{
FileInput(outputFile);
}
}
private static void FileInput(string outputFile)
{
Console.WriteLine("What is the name of the file?");
string titleFileName = Console.ReadLine();
StreamReader reader;
reader = new StreamReader(titleFileName);
string textFile = reader.ReadToEnd();
reader.Close();
string[] values = textFile.Split(',', '\n');
List<Square> squares = new List<Square>();
for (int i = 0; i < values.Length;)
{
int valueNumsX = int.Parse(values[i].Trim());
int valueNumsY = int.Parse(values[i + 1].Trim());
Square squareQ = new Square(Color.FromName(values[i + 2].Trim()), valueNumsX, valueNumsY);
squares.Add(squareQ);
if (i == values.Length - 3)
{
SvgBuilder svgBuilder = new SvgBuilder();
string SVG = svgBuilder.Build(squares);
FileCreator Myfilecreater = new FileCreator();
Myfilecreater.Create(outputFile, SVG);
}
i = i + 3;
}
}
private static void ManInput(string outputFile)
{
Console.WriteLine("How many squares do you want in your SVG file?");
string squareCount = Console.ReadLine();
int numSquareCount = Convert.ToInt32(squareCount);
Console.WriteLine("What are the colors of your squares?");
string[] squareColor = new string[numSquareCount];
List<Square> squares = new List<Square>();
for (int i = 0; i < numSquareCount; i++)
{
squareColor[i] = Console.ReadLine();
Square squareQ = new Square(Color.FromName(squareColor[i]), i*4, 0, 200);
squares.Add(squareQ);
if (i == numSquareCount - 1)
{
SvgBuilder svgBuilder = new SvgBuilder();
string SVG = svgBuilder.Build(squares);
FileCreator Myfilecreater = new FileCreator();
Myfilecreater.Create(outputFile, SVG);
}
}
}
}
}`
First of all you should separate classes or methods handling input from classes handling output. If is also typically a poor idea to mix UI from the functional parts, even if the the UI is a console for this case.
I would suggest using the following methods:
private static IEnumerable<Square> ReadSquaresFromFile(string filePath)
private static IEnumerable<Square> ReadSquaresFromConsole()
private static WriteToFile(IEnumerable<Square> squares, string filePath)
For such a simple program procedural programming should be just fine. You do not have to use object. But if you want to, you could for example create a interface like:
public interface ISquareSource(){
IEnumerable<Square> Get();
}
With a file-implementation, console-implementation etc.
Note that I have used string filePath as the file source/destination. If you ever write a library or API, please ensure you have an overlay that takes a stream. It is super annoying to have some data in memory and being forced to write it to a temporary file just because some developer only imagined reading from actual files.
You could also consider using switch statements for handling input, for example
switch(fileRead.Trim().ToLower()){
case "manually":
...
break;
case "file":
...
break;
default:
Console.WriteLine("Invalid input, expected 'manually' or 'file'
break;
Cohesion is the idea that code that does the same thing belongs together, and code that doesn't do the same thing doesn't belong together.
So, let's consider the FileInput function. At a glance, we can see that it does the following:
Prompts the user for a file name to load.
Opens the file.
Reads all of its content into memory.
Closes the file.
Parses the file content into an array of strings.
For each item in the array:
Parses some integral values.
Creates a Square object from those values.
If the index of the current item is equal to the length of the array less 3:
Instantiates a new SvgBuilder.
Invokes its Build method.
Instantiates a new FileCreator.
Invokes its Create method.
There's a lot going on here. Essentially, there are three separate kinds of work going on here that could be broken out into individual functions:
User input (arguably this could be part of the main function).
Call file deserialization function (reads the input file into memory and returns it as an array of strings).
Call main processing function (iterates over the array)
Performs calculations and creates of Square object.
If index of the current item is array length less 3:
Call Build SVG File function
Call File Creation function.
This is what your instructor is getting at.
I'm trying to write to a file at the moment I create my HighScores object. I'm trying to use the Name and Score properties as the text to the file, but they seem to be null and 0 respectively even though I initialized the object. So my question is why is it not writing "David : 88 "?
static void Main(string[] args)
{
HighScores David = new HighScores() { Name = "David", Score = 88 };
}
class HighScores
{
public string Name { get; set; }
private int score;
public int Score
{
get
{
if (score < 50)
{
return 0;
}
return score;
}
set
{
score = value;
}
}
public HighScores()
{
// Opening and writing to the file
FileStream fileStream = File.OpenWrite(path);
StreamWriter writer = new StreamWriter(fileStream);
writer.Write($"{Name} : {Score} \n");
writer.Close();
}
}
I think the issue is that the Constructor runs before any of the "sets" in your code. Setting breakpoints in your code (in your constructor, in the property sets) and using Step Into, might help see what order all the code is being run in.
So, instead of writing the values in the constructor, refactor that into an actual method.
change the line
public HighScores()
to
public void SaveScores()
then add the line after you "new" up your object.
David.SaveScores();
That should work.
I'd also look into leveraging the using/Dispose pattern as well.
using (var fileStream = File.OpenWrite(path))
{
// do stuff
}
// dotNet will be sure to call Dispose and clean up the fileStream.
As Andre correctly points out, the “Constructor” public HighScores() is called when you create a new HighScores object like you have below.
HighScores David = new HighScores() { Name = "David", Score = 88 };
Unfortunately the properties Name and Score have not been initialized. Since it is a “Constructor” simply pass the variables as you would a normal constructor like below:
HighScores David = new HighScores("David", 88);
Then set the matching signature in the HighScores “Constructor” then you can set the properties and it should work as expected, however I agree with Andre as this (writing to file) should be a separate method and NOT part of the “Constructor” Hope that makes sense.
public HighScores(string name, int score) {
Name = name;
Score = score;
using (FileStream fileStream = File.OpenWrite(path)) {
StreamWriter writer = new StreamWriter(fileStream);
writer.Write($"{Name} : {Score} \n");
writer.Close();
}
}
.
I made an example program in order to get this going so I can actualy learn how to use it and aply it in my actual project.
In brief, my first try was writting the Person instance into the file, but I couldnt populate later a list with the different instances written (I only could see the first written, and the list had only 1 element). So I came up with saving the Person instance into a dictionary, writting the dictionary into the file, and then reading complete dictionary from file before adding a new element (Person instance), but I couldnt accomplish this either.
Let's say a I have a class Person
[Serializable]
public class Person
{
public string name, lname;
public int age;
public void newperson(string name,
string lname,
int age)
{
this.name = name;
this.lname = lname;
this.age = age;
}
}
in my main class I have two methods (honestly stolen from here, thanks #Daniel Schroeder #deadlydog) to write and read from file, through binary format.
Person nper = new Person(); //nper, an instance of Person
Dictionary<string, Person> dict = new Dictionary<string, Person>();
const string file = #"..\..\data.bin";
_
public static void WriteToBinaryFile<T>(string filePath, T objectToWrite, bool append = false)
{
using (Stream stream = File.Open(filePath, append ? FileMode.Append : FileMode.Create))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
binaryFormatter.Serialize(stream, objectToWrite);
}
}
_
public static T ReadFromBinaryFile<T>(string filePath)
{
using (Stream stream = File.Open(filePath, FileMode.Open))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
return (T)binaryFormatter.Deserialize(stream);
}
}
I kind of understand this methods, but, I would be unable to code/modify them, it exceeds my knowledge.
In order to test writting/reading I dragged a few textboxes and a button1
private void button1_Click(object sender, EventArgs e)
{
//saving textboxes to Person instance
nper.newperson(textBox4.Text, textBox5.Text, Convert.ToInt16(textBox6.Text));
//saving that object into a dictionary<string,Person> the key is the name, the object is the Person itself
dict[nper.name] = nper;
//Writting this dict
WriteToBinaryFile(file, dict, true);
}
Then, I dragged a few more separated textboxes to check the reading:
private void button2_Click(object sender, EventArgs e)
{
try
{
//read the file and save all into dict (is this working like I think it should? is dict, getting all the data from file?)
dict = ReadFromBinaryFile<Dictionary<string,Person>>(file);
//write into diferent textboxes the Person properties, for the key that matches with another text box that i fill manually to check
textBox1.Text = dict[tbSearch.Text].name;
textBox2.Text = dict[tbSearch.Text].lname;
textBox3.Text = dict[tbSearch.Text].age.ToString();
}
catch (Exception ex) { MessageBox.Show(ex.ToString()); }
in button2_Click is dict getting all the data from file?
edit: Try and result:
Let's say I fill the initial boxes with
John,
Doe,
40
click button1
then load another one,
Clark,
Kent,
50
If I write "John" in tbSearch I see full data of John (name, lastname and age)
If I fill with "Clark" I get a dictionary error "the key given was not present in the dictionary"
Set append parameter = false in WriteToBinaryFile(file, dict, false).
When first call of WriteToBinaryFile method executed BinaryFormatter write dictionary with one element, In second try write a dictionary with two element but appended to first write, So BinaryFormatter when try deserialize stream, read first section contains save dictionary with one key in first try (first button1 click).
I have looked all over for this. It could be me just typing the wrong thing in search I'm not sure. So, if you know a good tutorial or example of this please share. I'm trying to learn.
I have a C# Windows Form app I'm working on. I have information (movies in this case) saved in an XML file. I saved the xml file like this.
//Now we add new movie.
XmlElement nodRoot = doc.DocumentElement;
string allMyChildren = nodRoot.InnerText;
string capitalized = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(movieEditNameTextbox.Text);
int indexLookForNewMake = allMyChildren.IndexOf(capitalized);
if (indexLookForNewMake >= 0)
{
MessageBox.Show("Movie is already saved.", "Error");
}
else
{
XmlElement el = doc.CreateElement("Name");
el.InnerText = capitalized;
doc.DocumentElement.AppendChild(el);
//Check if Year is really a Number.
if (movieEditYearTextbox.Text.All(Char.IsDigit))
{
//Remove ' cause it gives errors.
string capitalizedFixed = capitalized.Replace("'", "");
string capitalizedFinalFixed = capitalizedFixed.Replace("\"", "");
//Assign Attribute to each New one.
el.SetAttribute("Name", capitalizedFinalFixed);
el.SetAttribute("Type", movieEditTypeDropdown.Text);
el.SetAttribute("Year", movieEditYearTextbox.Text);
//Reset all fields, they don't need data now.
movieEditNameTextbox.Text = "";
movieEditYearTextbox.Text = "";
movieEditTypeDropdown.SelectedIndex = -1;
removeMovieTextbox.Text = "";
doc.Save("movie.xml");
label4.Text = "Movie Has been Edited";
loadXml();
}
else
{
//Error out. Year not a Number
MessageBox.Show("Check movie year. Seems it isn't a number.", "Error");
}
}
That all works fine. Now what I'm trying to do is make it where you can choose a directory, and it search the directory and sub directories and get file names and save them into the XML file.
I used this to try to accomplish this. It does pull the list. But it doesn't save it. It don't save the new information.
I can't use LINQ as it cause a confliction for some reason with other code.
DirectoryInfo dirCustom = new DirectoryInfo(#"D:\Video");
FileInfo[] filCustom;
filCustom = dirCustom.GetFiles("*",SearchOption.AllDirectories);
//Open XML File.
XmlDocument doc = new XmlDocument();
doc.Load("movie.xml");
XmlElement el = doc.CreateElement("Name");
string fulCustoms = filCustom.ToString();
foreach (FileInfo filFile in filCustom)
{
string capitalized = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(filFile.Name);
string capitalizedFixed = capitalized.Replace("\"", "");
el.SetAttribute("Name", capitalizedFixed);
el.SetAttribute("Type", "EDIT TYPE");
el.SetAttribute("Year", "EDIT YEAR");
richTextBox1.AppendText(capitalizedFixed + "\r\n");
}
doc.Save("movie.xml");
label4.Text = "Movie Has been Edited";
loadXml();
Now, the richTextBox does display the information correctly but it don't save it.
The loadXml() is just my noobish way to refresh the datagridview.
I'm completely lost and don't know where to turn to. I know my coding is probarely horrible, lol. I'm new to this. This is my first more complex application I have worked on.
I can't think of anymore information that would help you understand what I mean. I hope you do.
Thank you so much for your help.
Not sure exactly what your LoadXML() method does but my only piece of advise with your issue is to change the way you are implementing this functionality.
Create an object called Movie
public class Movie
{
public Movie() {}
public String Title { get; set; }
blah... blah...
}
Then create a MovieList
public class MovieList : List<Movie> { }
Then implement the following 2 methods inside the MovieList.
public static void Serialize(String path, MovieList movieList)
{
XmlSerializer serializer = new XmlSerializer(typeof(MovieList));
using (StreamWriter streamWriter = new StreamWriter(path))
{
serializer.Serialize(streamWriter, movieList);
}
}
public static MovieList Deserialize(String path)
{
XmlSerializer serializer = new XmlSerializer(typeof(MovieList));
using (StreamReader streamReader = new StreamReader(path))
{
return (MovieList) serializer.Deserialize(streamReader);
}
}
Thats it... You now have your object serialized and you can retrieve the data to populate through binding or whatever other methods you choose.
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Closed 10 years ago.
What's the best way to import a CSV file into a strongly-typed data structure?
Microsoft's TextFieldParser is stable and follows RFC 4180 for CSV files. Don't be put off by the Microsoft.VisualBasic namespace; it's a standard component in the .NET Framework, just add a reference to the global Microsoft.VisualBasic assembly.
If you're compiling for Windows (as opposed to Mono) and don't anticipate having to parse "broken" (non-RFC-compliant) CSV files, then this would be the obvious choice, as it's free, unrestricted, stable, and actively supported, most of which cannot be said for FileHelpers.
See also: How to: Read From Comma-Delimited Text Files in Visual Basic for a VB code example.
Use an OleDB connection.
String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\InputDirectory\\;Extended Properties='text;HDR=Yes;FMT=Delimited'";
OleDbConnection objConn = new OleDbConnection(sConnectionString);
objConn.Open();
DataTable dt = new DataTable();
OleDbCommand objCmdSelect = new OleDbCommand("SELECT * FROM file.csv", objConn);
OleDbDataAdapter objAdapter1 = new OleDbDataAdapter();
objAdapter1.SelectCommand = objCmdSelect;
objAdapter1.Fill(dt);
objConn.Close();
If you're expecting fairly complex scenarios for CSV parsing, don't even think up of rolling our own parser. There are a lot of excellent tools out there, like FileHelpers, or even ones from CodeProject.
The point is this is a fairly common problem and you could bet that a lot of software developers have already thought about and solved this problem.
I agree with #NotMyself. FileHelpers is well tested and handles all kinds of edge cases that you'll eventually have to deal with if you do it yourself. Take a look at what FileHelpers does and only write your own if you're absolutely sure that either (1) you will never need to handle the edge cases FileHelpers does, or (2) you love writing this kind of stuff and are going to be overjoyed when you have to parse stuff like this:
1,"Bill","Smith","Supervisor", "No Comment"
2 , 'Drake,' , 'O'Malley',"Janitor,
Oops, I'm not quoted and I'm on a new line!
Brian gives a nice solution for converting it to a strongly typed collection.
Most of the CSV parsing methods given don't take into account escaping fields or some of the other subtleties of CSV files (like trimming fields). Here is the code I personally use. It's a bit rough around the edges and has pretty much no error reporting.
public static IList<IList<string>> Parse(string content)
{
IList<IList<string>> records = new List<IList<string>>();
StringReader stringReader = new StringReader(content);
bool inQoutedString = false;
IList<string> record = new List<string>();
StringBuilder fieldBuilder = new StringBuilder();
while (stringReader.Peek() != -1)
{
char readChar = (char)stringReader.Read();
if (readChar == '\n' || (readChar == '\r' && stringReader.Peek() == '\n'))
{
// If it's a \r\n combo consume the \n part and throw it away.
if (readChar == '\r')
{
stringReader.Read();
}
if (inQoutedString)
{
if (readChar == '\r')
{
fieldBuilder.Append('\r');
}
fieldBuilder.Append('\n');
}
else
{
record.Add(fieldBuilder.ToString().TrimEnd());
fieldBuilder = new StringBuilder();
records.Add(record);
record = new List<string>();
inQoutedString = false;
}
}
else if (fieldBuilder.Length == 0 && !inQoutedString)
{
if (char.IsWhiteSpace(readChar))
{
// Ignore leading whitespace
}
else if (readChar == '"')
{
inQoutedString = true;
}
else if (readChar == ',')
{
record.Add(fieldBuilder.ToString().TrimEnd());
fieldBuilder = new StringBuilder();
}
else
{
fieldBuilder.Append(readChar);
}
}
else if (readChar == ',')
{
if (inQoutedString)
{
fieldBuilder.Append(',');
}
else
{
record.Add(fieldBuilder.ToString().TrimEnd());
fieldBuilder = new StringBuilder();
}
}
else if (readChar == '"')
{
if (inQoutedString)
{
if (stringReader.Peek() == '"')
{
stringReader.Read();
fieldBuilder.Append('"');
}
else
{
inQoutedString = false;
}
}
else
{
fieldBuilder.Append(readChar);
}
}
else
{
fieldBuilder.Append(readChar);
}
}
record.Add(fieldBuilder.ToString().TrimEnd());
records.Add(record);
return records;
}
Note that this doesn't handle the edge case of fields not being deliminated by double quotes, but meerley having a quoted string inside of it. See this post for a bit of a better expanation as well as some links to some proper libraries.
I was bored so i modified some stuff i wrote. It try's to encapsulate the parsing in an OO manner whle cutting down on the amount of iterations through the file, it only iterates once at the top foreach.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
// usage:
// note this wont run as getting streams is not Implemented
// but will get you started
CSVFileParser fileParser = new CSVFileParser();
// TO Do: configure fileparser
PersonParser personParser = new PersonParser(fileParser);
List<Person> persons = new List<Person>();
// if the file is large and there is a good way to limit
// without having to reparse the whole file you can use a
// linq query if you desire
foreach (Person person in personParser.GetPersons())
{
persons.Add(person);
}
// now we have a list of Person objects
}
}
public abstract class CSVParser
{
protected String[] deliniators = { "," };
protected internal IEnumerable<String[]> GetRecords()
{
Stream stream = GetStream();
StreamReader reader = new StreamReader(stream);
String[] aRecord;
while (!reader.EndOfStream)
{
aRecord = reader.ReadLine().Split(deliniators,
StringSplitOptions.None);
yield return aRecord;
}
}
protected abstract Stream GetStream();
}
public class CSVFileParser : CSVParser
{
// to do: add logic to get a stream from a file
protected override Stream GetStream()
{
throw new NotImplementedException();
}
}
public class CSVWebParser : CSVParser
{
// to do: add logic to get a stream from a web request
protected override Stream GetStream()
{
throw new NotImplementedException();
}
}
public class Person
{
public String Name { get; set; }
public String Address { get; set; }
public DateTime DOB { get; set; }
}
public class PersonParser
{
public PersonParser(CSVParser parser)
{
this.Parser = parser;
}
public CSVParser Parser { get; set; }
public IEnumerable<Person> GetPersons()
{
foreach (String[] record in this.Parser.GetRecords())
{
yield return new Person()
{
Name = record[0],
Address = record[1],
DOB = DateTime.Parse(record[2]),
};
}
}
}
}
There are two articles on CodeProject that provide code for a solution, one that uses StreamReader and one that imports CSV data using the Microsoft Text Driver.
A good simple way to do it is to open the file, and read each line into an array, linked list, data-structure-of-your-choice. Be careful about handling the first line though.
This may be over your head, but there seems to be a direct way to access them as well using a connection string.
Why not try using Python instead of C# or VB? It has a nice CSV module to import that does all the heavy lifting for you.
I had to use a CSV parser in .NET for a project this summer and settled on the Microsoft Jet Text Driver. You specify a folder using a connection string, then query a file using a SQL Select statement. You can specify strong types using a schema.ini file. I didn't do this at first, but then I was getting bad results where the type of the data wasn't immediately apparent, such as IP numbers or an entry like "XYQ 3.9 SP1".
One limitation I ran into is that it cannot handle column names above 64 characters; it truncates. This shouldn't be a problem, except I was dealing with very poorly designed input data. It returns an ADO.NET DataSet.
This was the best solution I found. I would be wary of rolling my own CSV parser, since I would probably miss some of the end cases, and I didn't find any other free CSV parsing packages for .NET out there.
EDIT: Also, there can only be one schema.ini file per directory, so I dynamically appended to it to strongly type the needed columns. It will only strongly-type the columns specified, and infer for any unspecified field. I really appreciated this, as I was dealing with importing a fluid 70+ column CSV and didn't want to specify each column, only the misbehaving ones.
I typed in some code. The result in the datagridviewer looked good. It parses a single line of text to an arraylist of objects.
enum quotestatus
{
none,
firstquote,
secondquote
}
public static System.Collections.ArrayList Parse(string line,string delimiter)
{
System.Collections.ArrayList ar = new System.Collections.ArrayList();
StringBuilder field = new StringBuilder();
quotestatus status = quotestatus.none;
foreach (char ch in line.ToCharArray())
{
string chOmsch = "char";
if (ch == Convert.ToChar(delimiter))
{
if (status== quotestatus.firstquote)
{
chOmsch = "char";
}
else
{
chOmsch = "delimiter";
}
}
if (ch == Convert.ToChar(34))
{
chOmsch = "quotes";
if (status == quotestatus.firstquote)
{
status = quotestatus.secondquote;
}
if (status == quotestatus.none )
{
status = quotestatus.firstquote;
}
}
switch (chOmsch)
{
case "char":
field.Append(ch);
break;
case "delimiter":
ar.Add(field.ToString());
field.Clear();
break;
case "quotes":
if (status==quotestatus.firstquote)
{
field.Clear();
}
if (status== quotestatus.secondquote)
{
status =quotestatus.none;
}
break;
}
}
if (field.Length != 0)
{
ar.Add(field.ToString());
}
return ar;
}
If you can guarantee that there are no commas in the data, then the simplest way would probably be to use String.split.
For example:
String[] values = myString.Split(',');
myObject.StringField = values[0];
myObject.IntField = Int32.Parse(values[1]);
There may be libraries you could use to help, but that's probably as simple as you can get. Just make sure you can't have commas in the data, otherwise you will need to parse it better.