String C# Tutorial

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  4. Use LastIndexOf(Char) to find the last directory separator character in a string and to extract the file name
using System;
using System.IO;
public class MainClass
{
   public static void Main()
   {
      string filename;
      filename = ExtractFilename(@"C:\temp\notafile.txt");
      Console.WriteLine("{0}", String.IsNullOrEmpty(filename) ? "" : filename);
   }
   public static string ExtractFilename(string filepath)
   {
      if (filepath.Trim().EndsWith(@"\"))
         return String.Empty;
      int position = filepath.LastIndexOf('\\');
      if (position == -1)
      {
         if (File.Exists(Environment.CurrentDirectory + Path.DirectorySeparatorChar + filepath)) 
            return filepath;
         else
            return String.Empty;
      }
      else
      {
         if (File.Exists(filepath))
            return filepath.Substring(position + 1);
         else
            return String.Empty;
      }
   }
}