您是否尝试过重新排序调用以便在实例化客户端之前设置 MaxReceivedMessageSize?例如，

Have you tried re-ordering the calls so that you set the MaxReceivedMessageSize before instantiating the client? eg,

var binding = new wsHttpBinding();
binding.MaxReceivedMessageSize = Int32.MaxValue; 
var wcfClient = new WCFServiceTestClient(binding, strServiceURL); 

不过，这可能会也可能不会帮助您解决 400 错误.

This may or may not help your 400 error, though.