extract all email address from a text using c#

check this snippet

using System.IO;
using System.Text.RegularExpressions;
using System.Text;

class MailExtracter
{

    public static void ExtractEmails(string inFilePath, string outFilePath)
    {
        string data = File.ReadAllText(inFilePath); //read File 
        //instantiate with this pattern 
        Regex emailRegex = new Regex(@"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*",
            RegexOptions.IgnoreCase);
        //find items that matches with our pattern
        MatchCollection emailMatches = emailRegex.Matches(data);

        StringBuilder sb = new StringBuilder();

        foreach (Match emailMatch in emailMatches)
        {
            sb.AppendLine(emailMatch.Value);
        }
        //store to file
        File.WriteAllText(outFilePath, sb.ToString());
    }
}

Following works

public static void emas(string text)
{
    const string MatchEmailPattern =
      @"(([\w-]+\.)+[\w-]+|([a-zA-Z]{1}|[\w-]{2,}))@"
      + @"((([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\.([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\."
      + @"([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\.([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])){1}|"
      + @"([a-zA-Z]+[\w-]+\.)+[a-zA-Z]{2,4})";

     Regex rx = new Regex(
       MatchEmailPattern,
       RegexOptions.Compiled | RegexOptions.IgnoreCase);

     // Find matches.
      MatchCollection matches = rx.Matches(text);

     // Report the number of matches found.
     int noOfMatches = matches.Count;

     // Report on each match.
     foreach (Match match in matches)
     {
       Console.WriteLine(match.Value.ToString());
     }
}

Just remove the "^" from the beginning and the "$" from the end of your filter string.

give this a try http://www.regular-expressions.info/email.html