美好的一天!
我有自定义popupcontainer control
- comboBox,您可以在其中放置其他控件,它们将在弹出窗口中显示。就我而言,它包含datagrid
。我想让它快速工作 - 只有当用户决定弹出我的控件时才需要datagrid。我决定将datagrid创建移动到其他线程并使用Backgroundworker
,因为它非常适合UI,我不想乱用Control.Invoke。这是我的简化代码:
protected override void OnCreateControl()
{
base.OnCreateControl();
CreateContainer();
}
protected virtual void CreateContainer()
{
_worker = new BackgroundWorker();
_worker.DoWork += DoActionsOnAsyncWork;
_worker.RunWorkerCompleted += AsyncWorker_RunWorkerCompleted;
_worker.RunWorkerAsync(this);
}
protected void DoActionsOnAsyncWork(object sender, DoWorkEventArgs e)
{
var _grid = ///Create and initialize local grid here
e.Result = _grid; // Throw it to RunWorkerCompleted event
}
private void AsyncWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (!e.Cancelled && e.Error == null && !IsDisposed && !IsDisposing)
{
if (!_closing)
{
this.Grid = e.Result as MyGrid;
AttachEventHandlersToGrid();
} else
(e.Result as MyGrid).Dispose(); // Get rid of grid
}
// Get rid of worker
_worker.DoWork -= DoActionsOnAsyncWork;
_worker.RunWorkerCompleted -= AsyncWorker_RunWorkerCompleted;
_worker.Dispose();
_worker = null;
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
WaitForBackgroundWorker();
// Dispose other stuff
...
}
base.Dispose(disposing);
}
protected void WaitForBackgroundWorker()
{
if (_worker == null ||
!_worker.IsBusy)
return;
_closing = true;
while (_worker != null && _worker.IsBusy)
Application.DoEvents(); // Hack throw worker.RunWorkerCompleted on top of msg queue
}
现在,我需要等待_worker
才能正确处理我的控件(表单范围更大)。此外_worker
创建grid
,也需要处理。我的问题是 - 如果没有Application.DoEvents(),我怎么能等待backgroundworker
。因为有时(通常在远程桌面上 - 可能是其他一些绘画算法?)它会导致整个应用程序挂起。调用堆栈:
mscorlib.dll!System.Threading.WaitHandle.InternalWaitOne(System.Runtime.InteropServices.SafeHandle waitableSafeHandle, long millisecondsTimeout, bool hasThreadAffinity, bool exitContext) + 0x1f bytes
mscorlib.dll!System.Threading.WaitHandle.WaitOne(long timeout, bool exitContext) + 0x23 bytes
mscorlib.dll!System.Threading.WaitHandle.WaitOne(int millisecondsTimeout, bool exitContext) + 0x1c bytes
System.Windows.Forms.dll!System.Windows.Forms.Control.WaitForWaitHandle(System.Threading.WaitHandle waitHandle) + 0x96 bytes
System.Windows.Forms.dll!System.Windows.Forms.Control.MarshaledInvoke(System.Windows.Forms.Control caller, System.Delegate method, object[] args, bool synchronous) + 0x34b bytes
System.Windows.Forms.dll!System.Windows.Forms.Control.Invoke(System.Delegate method, object[] args) + 0x50 bytes
System.Windows.Forms.dll!System.Windows.Forms.WindowsFormsSynchronizationContext.Send(System.Threading.SendOrPostCallback d, object state) + 0x56 bytes
System.dll!Microsoft.Win32.SystemEvents.SystemEventInvokeInfo.Invoke(bool checkFinalization, object[] args) + 0x66 bytes
System.dll!Microsoft.Win32.SystemEvents.RaiseEvent(bool checkFinalization, object key, object[] args) + 0x110 bytes
System.dll!Microsoft.Win32.SystemEvents.RaiseEvent(object key, object[] args) + 0xe bytes
System.dll!Microsoft.Win32.SystemEvents.OnUserPreferenceChanged(int msg, System.IntPtr wParam, System.IntPtr lParam) + 0x76 bytes
System.dll!Microsoft.Win32.SystemEvents.WindowProc(System.IntPtr hWnd, int msg, System.IntPtr wParam, System.IntPtr lParam) + 0x2c6 bytes
[Native to Managed Transition]
[Managed to Native Transition]
System.Windows.Forms.dll!System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(System.IntPtr dwComponentID, int reason, int pvLoopData) + 0x357 bytes
System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(int reason, System.Windows.Forms.ApplicationContext context) + 0x33d bytes
System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoop(int reason, System.Windows.Forms.ApplicationContext context) + 0x5f bytes
System.Windows.Forms.dll!System.Windows.Forms.Application.DoEvents() + 0x18 bytes
MyControl.WaitForBackgroundWorker() Line 874 + 0x1b bytes
... // Many recursive disposes
Form.Dispose()
答案 0 :(得分:1)
由于这一行:
while (_worker != null && _worker.IsBusy)
Application.DoEvents(); // Hack throw worker.RunWorkerCompleted on top of msg queue
即使DoWork已经完成,你的while循环也会阻止RunWorkerCompleted执行,因为它们在同一个线程中(循环继续执行。
更改代码如下:
private void AsyncWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (!e.Cancelled && e.Error == null && !IsDisposed && !IsDisposing)
{
if (!_closing)
{
this.Grid = e.Result as MyGrid;
AttachEventHandlersToGrid();
}
else
{
(e.Result as MyGrid).Dispose(); // Get rid of grid
}
}
// Get rid of worker
_worker.DoWork -= DoActionsOnAsyncWork;
_worker.RunWorkerCompleted -= AsyncWorker_RunWorkerCompleted;
_worker.Dispose();
_worker = null;
if(_closing)
this.Dispose(); //call Dispose again, now you know that worker has finished
}
protected bool HasBackgroundWorkerFinished()
{
if (_worker == null ||
!_worker.IsBusy)
return true;
_worker.CancelAsync();
_closing = true; //this means that worker is busy
return false;
}
protected override void Dispose(bool disposing)
{
bool dispose = true;
if (disposing)
{
dispose = HasBackgroundWorkerFinished();
if (dispose)
{
// Dispose other stuff
}
}
if(dispose) //don't dispose if worker didn't finish
base.Dispose(disposing);
}
将_worker设置为接受取消并多次添加此代码
if (_worker.CancellationPending)
{
e.Cancel = true;
return;
}
到所有主要代码部分之间的DoWork代码