Question

I’m looking for String extension methods for TrimStart() and TrimEnd() that accept a string parameter.

I could build one myself but I’m always interested in seeing how other people do things.

How can this be done?

Answer 1

To trim all occurrences of the (exactly matching) string, you can use something like the following:

TrimStart

public static string TrimStart(this string target, string trimString)
{
    if (string.IsNullOrEmpty(trimString)) return target;

    string result = target;
    while (result.StartsWith(trimString))
    {
        result = result.Substring(trimString.Length);
    }

    return result;
}

TrimEnd

public static string TrimEnd(this string target, string trimString)
{
    if (string.IsNullOrEmpty(trimString)) return target;

    string result = target;
    while (result.EndsWith(trimString))
    {
        result = result.Substring(0, result.Length - trimString.Length);
    }

    return result;
}

To trim any of the characters in trimChars from the start/end of target (e.g. "foobar'@"@';".TrimEnd(";@'") will return "foobar") you can use the following:

TrimStart

public static string TrimStart(this string target, string trimChars)
{
    return target.TrimStart(trimChars.ToCharArray());
}

TrimEnd

public static string TrimEnd(this string target, string trimChars)
{
    return target.TrimEnd(trimChars.ToCharArray());
}