NetworkCredential.Domain Property

    // Create an empty instance of the NetworkCredential class.
    NetworkCredential myCredentials = new NetworkCredential("","","");
    myCredentials.Domain = domain;
    myCredentials.UserName = username;
    myCredentials.Password = passwd;

    // Create a WebRequest with the specified URL. 
    WebRequest myWebRequest = WebRequest.Create(url); 
    myWebRequest.Credentials = myCredentials;
    Console.WriteLine("\n\nUser Credentials:- Domain : {0} , UserName : {1} , Password : {2}",myCredentials.Domain,myCredentials.UserName,myCredentials.Password);

    // Send the request and wait for a response.
    Console.WriteLine("\n\nRequest to Url is sent.Waiting for response...Please wait ...");
    WebResponse myWebResponse = myWebRequest.GetResponse();

    // Process the response.
    Console.WriteLine("\nResponse received sucessfully");

    // Release the resources of the response object.
    myWebResponse.Close();