C# 删除wcf服务调用上的事件处理程序
我最近遇到了以下代码:C# 删除wcf服务调用上的事件处理程序,c#,wcf,C#,Wcf,我最近遇到了以下代码: public static class ClientBaseExtender { /// <summary> /// Tries to execute async service call. If <see cref="TimeoutException"/> occured retries again. /// </summary> /// <typeparam name="TCh
public static class ClientBaseExtender
{
/// <summary>
/// Tries to execute async service call. If <see cref="TimeoutException"/> occured retries again.
/// </summary>
/// <typeparam name="TChannel">ServiceClient class.</typeparam>
/// <typeparam name="TArgs">Type of service client method return argument.</typeparam>
/// <param name="client">ServiceClient instance.</param>
/// <param name="tryExecute">Delegate that execute starting of service call.</param>
/// <param name="onCompletedSubcribe">Delegate that subcribes an event handler to the OnCompleted event of the service client method.</param>
/// <param name="onCompleted">Delegate that executes when service call is succeeded.</param>
/// <param name="onError">Delegate that executes when service call fails.</param>
/// <param name="maxAttempts">Maximum attempts to execute service call before error if <see cref="TimeoutException"/> occured (by default 5).</param>
public static void ExecuteAsyncRepeatedly<TChannel, TArgs>(this ClientBase<TChannel> client, Action tryExecute,
Action<EventHandler<TArgs>> onCompletedSubcribe, EventHandler<TArgs> onCompleted,
EventHandler<TArgs> onError, int maxAttempts)
where TChannel : class
where TArgs : AsyncCompletedEventArgs
{
int attempts = 0;
var serviceName = client.GetType().Name;
onCompletedSubcribe((s, e) =>
{
if (e.Error == null) // Everything is OK
{
if (onCompleted != null)
onCompleted(s, e);
((ICommunicationObject)client).Close();
Debug.WriteLine("[{1}] Service '{0}' closed.", serviceName, DateTime.Now);
}
else if (e.Error is TimeoutException)
{
attempts++;
if (attempts >= maxAttempts) // Final timeout after n attempts
{
Debug.WriteLine("[{2}], Final Timeout occured in '{0}' service after {1} attempts.", serviceName, attempts, DateTime.Now);
if (onError != null)
onError(s, e);
client.Abort();
Debug.WriteLine("[{1}] Service '{0}' aborted.", serviceName, DateTime.Now);
return;
}
// Local timeout
Debug.WriteLine("[{2}] Timeout occured in '{0}' service (attempt #{1}).", serviceName, attempts, DateTime.Now);
Debug.WriteLine("[{2}] Attempt #{0} to execute call to '{1}' service.", attempts + 1, serviceName, DateTime.Now);
tryExecute(); // Try again.
}
else
{
if (onError != null)
onError(s, e);
client.Abort();
Debug.WriteLine("[{1}] Service '{0}' aborted.", serviceName, DateTime.Now);
}
});
Debug.WriteLine("[{2}] Attempt #{0} to execute call to '{1}' service.", attempts + 1, serviceName, DateTime.Now);
tryExecute(); // First attempt to execute
}
}
public void GetData()
{
var client = new MyServiceClient();
client.ExecuteAsyncRepeatedly(() => client.MyOperationAsync(...),
(EventHandler<MyOperationCompletedEventArgs> handler) =>client.MyOperationCompleted += handler,
(s, e) => // OnCompleted
{
Do(e.Result);
},
(s, e) => // OnError
{
HandleError(e.Error);
}
);
我认为可以通过在代码中实现推拉策略来解决这个问题。我提出类似的建议:
bool _requestPending;
readonly object _lock = new object();
void OnClick (...)
{
lock(_lock)
{
if (_requestPending == false)
{
_dataService.GetData(GetDataCompleted);
_requestPending = true;
}
}
}
private void GetDataComplete(Data data)
{
lock(_lock)
{
try
{
//do something with data
}
finally
{
_requestPending = false;
}
}
}
更好的是,当您有一个挂起的请求时,禁用UI按钮。从不同线程访问和修改_requestPending不会有任何并发性问题,但如果服务响应足够快,仍然可能会出现争用情况,因此最好同步两个代码块
不管怎样,就我个人而言,我不喜欢你试图实现的这个实现。代码非常混乱,并且很难预见可能出现的问题。确保:
- 您提供了一种中止请求的方法 然后再次启用按钮
- 更新屏幕的代码是 由UI线程执行
bool _requestPending;
readonly object _lock = new object();
void OnClick (...)
{
lock(_lock)
{
if (_requestPending == false)
{
_dataService.GetData(GetDataCompleted);
_requestPending = true;
}
}
}
private void GetDataComplete(Data data)
{
lock(_lock)
{
try
{
//do something with data
}
finally
{
_requestPending = false;
}
}
}