Hi ,
You can use RegEx to extract the number and/or string.
Try following code
string myStr = "1ab2n3";
string myNumberResult = Regex.Replace(myStr, @"[^\d]", "");
string myCharResult = Regex.Replace(myStr, @"[\d]", "");
Hope that helps. If it does, mark the it as answer/upvote.
-Milind