Good old VB functions in c# Left, Mid, Right

Missing the good old string functions in c# I wanted to recreate them.
This is my solution where they are resurrected as extension methods.

public static class StringHelper
{
    public static string Right(this String source, int length)
    {
        if (source.Length == 0 || length <= 0)
        {
        return "";
        }

        return source.Substring(source.Length - length, length);
    }

    public static string Left(this String source, int length)
    {
        if (source.Length == 0 || length <= 0)
        {
        return "";
        }

        return source.Substring(0, length);
    }

    public static string Mid(this string source, int startIndex, int length)
    {
        if (source.Length == 0 || length <= 0 || startIndex < 0)
        {
        return "";
        }
        return source.Substring(startIndex, length);
    }

    public static string Mid(this string source, int startIndex)
    {
        if (source.Length == 0 || startIndex < 0)
        {
        return "";
        }
        return source.Substring(startIndex);
    }
}

To keep the code from giving errors I check for the length parameter,
if this is not what you want, you can throw an argumentexception for example ...

Getting the temp folder in c#

Another reminder to myself :

To get the temp path in c#, the most used option I have seen is :

string tempPath = Environment.GetEnvironmentVariable("Temp");

which works ok most of the time, but personally I don't like to pass string variables around,
so I went looking for something as :
string tempPath = Environment.GetFolderPath(SpecialFolder.Temp);
which ofcourse does not exist.

But as with google as a friend, I found the best way (for me) :

String tempPath = Path.GetTempPath();

(always in the last place you look of course ;-) )

Using double quotes in c#

As a 'convert' (rather forced) from VB.NET to C# I always miss how to use the double quotes in a string, so here just as a reminder to myself :
use the @ symbol before the string or doubling the quotes won't help:

string myString = @"SomeText which needs a ""quote";

ofcourse, at the beginning of the string or the end of the string just triple the quotes :
string myString = @"SomeText which needs some ""quotes""";

But the most important is : use the @