Trim string from the end of a string in .NET - why is this missing?

Question

I need this all the time and am constantly frustrated that the Trim(), TrimStart() and TrimEnd() functions don\'t take strings as inputs. You call EndsWith() on a string, an

Answer 1

I like my TrimEnd to remove all the instances of the string at the end and not just the last one.

public static string TrimEnd(this string str, string trimStr)
{
    if (string.IsNullOrEmpty(str) || string.IsNullOrEmpty(trimStr)) return str;

    while(str.EndsWith(trimStr))
    {
        str = str.Remove(str.LastIndexOf(trimStr));
    }
    return str;
}