异步调用WCF的方法需要小心的地方

直接使用下面的代码，由于client对象占用的资源没有被释放，会导致内存泄露
GetSimServiceReference.GetSimServiceClient client = new GetSimServiceReference.GetSimServiceClient()
client.computerSimAsync(DepartmentNo, FileID, F_intput.Length, ReadStringArrayFromStrings());
上面的问题，可以使用下面的方法来避免

                    using (GetSimServiceReference.GetSimServiceClient client = new GetSimServiceReference.GetSimServiceClient())
                    {
                        client.computerSimA(DepartmentNo, FileID, F_intput.Length, ReadStringArrayFromStrings());
                    }

但是如果使用异步调用的方式，会导致调用不到远程服务，并且没有任何异常提示，很是让人摸不到头脑

                    using (GetSimServiceReference.GetSimServiceClient client = new GetSimServiceReference.GetSimServiceClient())
                    {
                       client.computerSimAsync(DepartmentNo, FileID, F_intput.Length, ReadStringArrayFromStrings());
                    }

最后，采用了如下的代码：
                 

                    try
                    {
                        GetSimServiceReference.GetSimServiceClient client = new GetSimServiceReference.GetSimServiceClient();
                        client.computerSim(DepartmentNo, FileID, F_intput.Length, ReadStringArrayFromStrings());
                        if (client.State != CommunicationState.Faulted) client.Close();

                    }
                    catch (CommunicationObjectFaultedException cofe)
                    {
                        ShowException.SaveLogAsTXTInfoex("调用WCF服务失败，异常信息：" + cofe.Message);
                    }
                    catch (Exception ex)
                    {
                        ShowException.SaveLogAsTXTInfoex("调用WCF服务失败，异常信息：" + ex.Message+f_intput.FullName);
                    }