Validate multiple emails on editor

Question

Hi,

I have editor and user insert multi emails sepertated by semicolon .

I need to validate them.

1. How I can valid them efficently. If you could give me how you validate email please look on IsValidEmail

method?

/// <summary>
 /// Check if email reciepents is valid
 /// </summary>
 /// <param name="reciepents">The reciepents seperated by coma(;)</param>
 /// <returns>Return true if reciepents string is valid, otherwise return false</returns>
 public static bool IsValidReciepents(string reciepents)
 {
     try
     {
         if (string.IsNullOrEmpty(reciepents))
         {
             return false;
         }
         string[] tmpEmails = reciepents.Split(new[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
         foreach (var address in tmpEmails.Select(s => s.Trim()).Distinct(StringComparer.InvariantCultureIgnoreCase).ToArray())
         {
             var isEmailValid = IsValidEmail(address);
             if (!isEmailValid)
             {
                 return false;
             }
         }
         return true;
     }
     catch (Exception ex)
     {
         _logger.Error("IsValidReciepents", ex);
         return false;
     }
 }

/// <summary>
  /// Check if input string is valid
  /// </summary>
  /// <param name="inputString">The input string to check</param>
  /// <returns>Return true if input string is valid, otherwise return false</returns>
  public static bool IsValidEmail(string inputString)
  {
      try
      {
          MailAddress mailAddress = new MailAddress(inputString);
          return true;
      }
      catch(Exception ex)
      {
          return false;
      }
  }

Thanks in advance,

Answer 1

It depends on how many emails you need to validate. If they're just a few, you can use MailAddres or even use a Regular Expression for it.

var pattern = @"^\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$"; 
if(Regex.IsMatch(val ?? "", pattern))
    // Do what you want

Another thing to think about is throw an exception... Do you really need it? All exceptions have a cost, so can be more efficient just do nothing.

Here's a complete example

// Let's supose you already have a property Email being filled with addresses separated by coma
public void OnSubmit()
{
    const string pattern = @"^\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$"; 
    var validEmails = new List<string>();
    foreach(var item in Email.Split(","))
    {
        if(Regex.IsMatch(item ?? "", pattern))
            validEmails.Add(item);
    }

    // Now you have a list with only valid emails
    ...
}