WCF cannot capture faultexception

There is a service error contract, such as businessfault.

Throw new faultexception <businessfault> (New businessfault (), errmessage );

After this throw, the client always receives a communicationexception instead of the preceding exception.CodePass

Businessfault = new businessfault {faultdetail = new faultdetail {errorcode = "businesserror", message = string. isnullorempty (errmessage )? Errmessage: "No message"}, invalidargumentdetail = new invalidargumentdetail ()}; throw new faultexception <businessfault> (businessfault, errmessage );

Why? After careful troubleshooting, it is found that some elements defined in the schema cannot be empty, such as error and message, but cannot be found by developers During writing or compiling. I think it would be nice to use the constructor to force a proxy class.