Question

Is it possible to use the method extensions to add methods that accept parameters ?

for example:

myString.NumberOfCharacters("a");

Answer 1

yes. like this

 

public static class StringExtensions
 {
    public static void NumberOfCharacters(this string someString, string param)
    {
       ...
    }
 }

Check out the MDSN page of extension methods and the examples there.