Get email address from mailbox alias using EWS

Here is a cool Exchange Web Service, Resolve Name, that you can use to get the email address from your mailbox alias.

This is a sample function:

private string GetEmailAddressFromUser(string alias)
{
        try
        {
                // SSL Certificate validation
                ServicePointManager.ServerCertificateValidationCallback =
                    delegate(Object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
                    {
                        // Aceptamos el certificado sin mirar
                        return true;
                    };

                // Initialize the EWS Service
                ExchangeServiceBinding ewsService = new ExchangeServiceBinding();

                // User's Credentials
                ewsService.Credentials = new NetworkCredential(m_Service_Credential_User, m_Service_Credential_Password, m_Service_Credential_Domain);

                // EWS Service URL and Proxy
                ewsService.Url = m_Service_Url;
                ewsService.Proxy = this.GetProxy();

                // Resolve Name Parameters 
                ResolveNamesType resolveNamesType = new ResolveNamesType();
                resolveNamesType.ReturnFullContactData = true;
                resolveNamesType.UnresolvedEntry = alias;

                // Invoke EWS Service
                ResolveNamesResponseType response = ewsService.ResolveNames(resolveNamesType);

                // Get the result
                ResolveNamesResponseMessageType root =
                   (ResolveNamesResponseMessageType)response.ResponseMessages.Items[0];

                // Check the result
                if (root.ResponseClass != ResponseClassType.Success)
                {
                    // Throw an Exception
                    throw new ApplicationException(string.Format("{0}.{1}.{2}", root.ResponseClass, root.ResponseCode, root.MessageText));                                  
                }
                else
                {
                    // Get the email address
                    return root.ResolutionSet.Resolution[0].Mailbox.EmailAddress;
            }
        }
        catch (Exception ex)
        {
                throw ex;
        }
}