System.Array. does not contain a definition for “ToList”

.net-3.5c#-3.0

I'm getting the above error on the ToList() line of the code below

if (emailReplyTo != null)
{
  System.Collections.Generic.List<String> replyto
    = emailReplyTo
    // Strip uneccessary spaces
    .Replace(", ", ",")
    .Split(',')
    .ToList();

  request.WithReplyToAddresses(emailReplyTo);
}

I have included using System.Collections; at the top of my file.
The target framework is 3.5, so why is this causing an error?

Best Answer

The ToList method you are looking for is an extension method. Try adding this using directive to the top of your file:

using System.Linq;

By adding this using directive you are indicating to the compiler that any extension methods in that namespace should be imported. It's kind of a shame that there isn't more help from Visual Studio around importing extension methods (ReSharper does this rather nicely).

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