Develop Reference

c# show underscore _ in date instead of dash -

I am saving a file name with a string value plus the date as follows:
var fileName = String.Format("{0}_{1}.zip", "fileName", DateTime.Now.ToString("yyyy-MM-dd"));
The above line gives me:
fileName_2015-11-24.zip
Is it some how possible that I can get fileName_2015_11_24.zip
I have actually tried with DateTime.Now.ToString("yyyy_MM_dd") But I forgot to mention in my question.
One possibility is to replace dashed - with underscores _ but is there any other solution ?
Thanks.

How about this?
String.Format("{0}_{1:yyyy_MM_dd}", "filename", DateTime.Now);
To clarify: You can use DateTime format parameters in String.Format itself.

Have you tried simply using underscores in your date format string?
DateTime.Now.ToString("yyyy_MM_dd")

Just replace - with _
var fileName = String.Format("fileName_{0}.zip", DateTime.Now.ToString("yyyy_MM_dd"));

You can provide formatting parameters for each value in your call to String.Format. Just add a custom formatting string after a colon (:), like this:
var fileName = String.Format("fileName_{0:yyyy_MM_dd}.zip", DateTime.Now);

You could do this
$"FileName_{DateTime.Now:MM_dd_yyyy}";

Convert HTML query to normal string

I have a webmethod and get my queryString with this code:
string name = "";
int pos7 = context.Request.UrlReferrer.PathAndQuery.IndexOf("name");
if (pos7 >= 0)
name = context.Request.UrlReferrer.PathAndQuery.Substring(pos7 + 5);
The problem is the adresse "www.test.com?name=tiki song" will be end up in "tiki%20song" on my string.
How to avoid that?
(Yes I could replace the %20 to " " but there are a lot of more of that kind, right?"

Consider using Uri.UnescapeDataString
http://msdn.microsoft.com/en-us/library/system.uri.unescapedatastring.aspx

As per this previous you could create a URI and extract it using "UnescapeDataString" (post). Referencing this MSDN page.
Or alternatively, you can use some of the HtmlDecode methods as MikeBarkemeyer had mentioned in the comments.

How to remove a certain substring in C#

So I have a few file extensions in my C# projects and I need to remove them from the file name if they are there.
So far I know I can check if a Sub-string is in a File Name.
if (stringValue.Contains(anotherStringValue))
{
// Do Something //
}
So if say stringValue is test.asm, and then it contains .asm, I want to somehow remove the .asm from stringValue.
How can I do this?

if you want a "blacklist" approach coupled with the Path library:
// list of extensions you want removed
String[] badExtensions = new[]{ ".asm" };
// original filename
String filename = "test.asm";
// test if the filename has a bad extension
if (badExtensions.Contains(Path.GetExtension(filename).ToLower())){
// it does, so remove it
filename = Path.GetFileNameWithoutExtension(filename);
}
examples processed:
test.asm = test
image.jpg = image.jpg
foo.asm.cs = foo.asm.cs <-- Note: .Contains() & .Replace() would fail

You can use Path.GetFileNameWithoutExtension(filepath) to do it.
if (Path.GetExtension(stringValue) == anotherStringValue)
{
stringValue = Path.GetFileNameWithoutExtension(stringValue);
}

No need for the if(), just use :
stringValue = stringValue.Replace(anotherStringValue,"");
if anotherStringValue is not found within stringValue, then no changes will occur.

One more one-liner approach to getting rid of only the ".asm" at the end and not any "asm" in the middle of the string:
stringValue = System.Text.RegularExpressions.Regex.Replace(stringValue,".asm$","");
The "$" matches the end of the string.
To match ".asm" or ".ASM" or any equivlanet, you can further specify Regex.Replace to ignore case:
using System.Text.RegularExpresions;
...
stringValue = Regex.Replace(stringValue,".asm$","",RegexOptions.IgnoreCase);

Changing an "." to an "_" in a C# string

I'm developing a piece of software in C# and the end result is an Excel spreadsheet. The title of the spreadsheet is created using several variables to explain exactly what the spreadsheet is. One of the variables is a string which contains data like this:
'1.1.1'
I need to convert it at the point of creating the spreadsheet to be:
'1_1_1'
I have tried using the String.Replace method but it just seems to ignore it. Any ideas?
Best Regards

I bet you doing this:
myString.Replace(".","_");
When you should be doing this:
myString = myString.Replace(".","_");
Remember, in .Net strings are immutable, so any changes result in a new string.

Chances are you're ignoring the result of string.Replace. You need:
text = text.Replace('.', '_');
Just calling Replace doesn't change the existing string - it creates a new string and returns it. Strings are immutable in .NET - they never change after creation.

When you use string.Replace are you remembering that you have to assign it?
yourString.Replace(".", "_");
Will do nothing.
string newString = yourString.Replace(".", "_");
will return the string with the dots replaced with underscores.

If I had to guess, you're not capturing the value returned by String.Replace. Strings are immutable, so String.Replace returns a new string, which you need to store a reference to.
string foo = "1.1.1";
foo = foo.Replace('.', '_');

String input = "1.1.1";
input = input.Replace(".", "_");

strings are immutable, so make sure you're using it like this:
string myString = "1.1.1";
myString = myString.Replace('.', '_');

String.Replace is the right way to do this:
private void button1_Click(object sender, RoutedEventArgs e) {
String myNumbers = "1.1.1";
Console.WriteLine("after replace: " + myNumbers);
myNumbers = myNumbers.Replace(".", "_");
Console.WriteLine("after replace: " + myNumbers);
}
will produce:
after replace: 1.1.1
after replace: 1_1_1

Look it to this Statement : System.Security.Principal.WindowsIdentity.GetCurrent().Name;

Look at this statement :
messageBox.show( System.Security.Principal.WindowsIdentity.GetCurrent().Name);
the output of this statement is :
Roshan\mohdibrahim.tasal
but i want to display me only :
mohdibrhaim.tasal
how can i do this?

You can just split the name on the "\" and retrieve the 2nd item.
e.g.
System.Security.Principal.WindowsIdentity.GetCurrent().Name.Split('\\')[1]
Edit:
You'll want to make this safe by first checking for the existence of a backslash - if there isn't one, you just want to take the Name as-is.

Why don't you trim returned value until '\' is reached,
following code does the trick
WindowsIdentity current = System.Security.Principal.WindowsIdentity.GetCurrent();
if(current!=null)
{
string name = current.Name;
string value = name.Substring(name.IndexOf('\\') + 1);
}

Environment.UserName should work without any splitting or additional logic.