I have an existing working WPF Application in which I have implemented my own custom authentication to a backend WCF service. When I access this service from WPF, setup the ServiceProxy as follows:
proxy.ClientCredentials.UserName.UserName = "test";
proxy.ClientCredentials.UserName.Password = "pass";
and because I'm using HTTPS the uid/pwd is secure.
In Silverlight 2 there is no .ClientCredentials object on the proxy. The only option I've found is to add two string parameters to EVERY WCF Exposed method for Uid/Pwd. That sounds like insanity to me, there MUST be a better way, no?
Unfortunately Silverlight 2 only supports basicHttpBinding which means it doesn't support ClientCredentials.
The 2 options you have are: 1. As you mentioned passing the username and pass with each request. 2. using asp.net authentication and enable asp.net compatability mode in your services.
-- N.B TransportSecurityWithMessageCredentials I mention below didn't seem to make the cut for SL3 so only options are the 2 above for both SL2 and SL3
Silverlight 3 improves on this story with TransportSecurityWithMessageCredentials and you can find out more about this on the Silverlight Web Services Team blog (Would link to it but apparently as I'm a new user I'm not allowed0
HTH
来源：https://stackoverflow.com/questions/885326/silverlight-wcf-authentication-help-going-from-wpf-to-silverlight