We can use regular expression to get the first N words from a title or strings. The following example shows how it can be done.
This example utilizes RegularExpression namespace
eg
using System.Text.RegularExpressions;
string testwords = "I want only first N words from this strings";
 string firstnWords = Regex.Match( testwords , @"^(\w+\b.*?){3}").ToString();
 label_Result.Text = firstnWords;
Result
I want only