Is it possible to create an extension method to format a string?

Question

the question is really simple. How do we format strings in C#? this way:

 string.Format(\"string goes here with placeholders like {0} {1}\", firstName, lastN         


        

Answer 1

Yes.       

public static string Format(this string str, string firstItem, string secondItem)
{
    return string.Format(str, firstItem, secondItem);
}

BTW, this method has to belong to a public and static class.