Working with string and replace

How about this:

str.Split('.').Last();

There are a whole bunch of useful methods on an instance of a string. The best place for you to look is on MSDN.

In your particular case you can use substring and lastindexof. If the case were more complicated I'd probably suggest RegEx although this is much more involved.

String str2 = str.SubString(str.LastIndexOf('.') + 1);

You Can use Split function Below like this :

String str = "Have.Fun.Something";
String str2 = "asd.sad.saw.sa.Something";

string[] Words= str.Split('.');

MessageBox.Show(Words[Words.Length-1].tostring());

Get Below like this

Something

Same as String str2 = "asd.sad.saw.sa.Something"; Thanks..!

You may use Regular Expressions (regex):

(?:.*)\.(?<myGroup>.*)

Applying the above regex, you'll have a group named 'myGroup' which has the value after the last dot

Personally, i like this options because it gives you further scalability if the need arises

If you need further assistance with regex, please say so

Bug free approach

public static string Substring(string input)
{
    if (!String.IsNullOrEmpty(input))
    {
        int lastIndex = input.LastIndexOf('.');
        if (lastIndex != -1)
            return input.Substring(lastIndex + 1);
    }

    return input;
}