Catch Unauthorized exception

I am connectin开发者_Go百科g to a webservice in my project by entereing user credentials(user name and password) i need to catch a unauthorized exception when the user enter invalid username/password. How can i do that

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Are you attempting to catch an exception before calling the webservice?

try
{
    result = Service.GetResult(param1, param2);
}
catch(System.Net.WebException ex)
{
    Logger.WriteError("Error calling Webservice: ", ex.ToString());
}

WebException will catch server return codes as errors I believe, such as HTTP status 404: Not Found etc.

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Is your web service SOAP? Are you using WCF on on the service side? If so, take a look at a Specifying and Handling Faults