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我正在开发像 TeraTerm 这样的 UART 终端程序。我正在制作自己的终端程序，因为我需要一些在其他终端程序中找不到的功能。

我的终端程序可以打开几个终端窗口，每个窗口都显示来自所选 COM 端口的输出。每个终端窗口都在自己的线程中运行。

我已经覆盖了终端窗口窗体的 WndProc 函数来捕获设备更改事件，因为我想用当前 PC 的可用 COM 端口更新 ComboBox 的项目。如果用户插入 USB COM 端口设备，这样做是为了使 COM 端口列表保持最新。

我的 WndProc 如下所示：

    protected override void WndProc(ref Message m)
    {
        switch(m.Msg)
        {
            case WM_DEVICECHANGE:
                GetAvailableCOMPorts();
                COMPortsComboBox.Invoke(UpdateCOMPortsComboBoxDelegate);
                break;
        }

        base.WndProc(ref m);
    }

UpdateCOMPortsComboBoxDelegate 是在发生设备更改时更新 ComboBox 中项目的函数。如果设备不是 COM 设备，则无关紧要。我不检查以保持简单。

委托所指向的 UpdateCOMPortsComboBox 函数如下所示：

    private void UpdateCOMPortsComboBox()
    {
        bool State                  = COMPortsComboBox.Enabled;
        COMPortsComboBox.Enabled    = false;           
        COMPortsComboBox.Items.Clear();
        COMPortsComboBox.Enabled    = State;

        // Then add the new list of COM ports
        for(int i = 0; i < AvailableSerialPorts.Length; i++)
        {
            COMPortsComboBox.Items.Add(AvailableSerialPorts[i]);
        }
    }

我的问题是我有时会在 Clear() 方法调用中得到 RaceOnRCW，即使我已经使用 Invoke 来确保在运行控制消息循环的线程上调用它。

到底是怎么回事？

我该如何防止这种情况发生？

或者，也许我怎样才能确定控件是否正在另一个线程上使用？然后也许等待另一个线程完成。

当设备更改事件发生时，是否有更好的方法来使用新列表更新 ComboBox 项？

调用堆栈发生时如下所示：

    mscorlib.dll!System.__ComObject.ReleaseSelf() + 0x5 bytes   
    mscorlib.dll!System.Runtime.InteropServices.Marshal.ReleaseComObject(object o) + 0x9a bytes 
    System.Windows.Forms.dll!System.Windows.Forms.StringSource.ReleaseAutoComplete() + 0x11 bytes   
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.OnHandleDestroyed(System.EventArgs e) + 0x85 bytes   
    System.Windows.Forms.dll!System.Windows.Forms.Control.WmDestroy(ref System.Windows.Forms.Message m) + 0x46 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.WndProc(ref System.Windows.Forms.Message m) + 0x44d bytes 
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.WndProc(ref System.Windows.Forms.Message m) + 0x882 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.OnMessage(ref System.Windows.Forms.Message m) + 0x13 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.WndProc(ref System.Windows.Forms.Message m) + 0x31 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.NativeWindow.DebuggableCallback(System.IntPtr hWnd, int msg, System.IntPtr wparam, System.IntPtr lparam) + 0x64 bytes 
    [Native to Managed Transition]  
    [Managed to Native Transition]  
    System.Windows.Forms.dll!System.Windows.Forms.UnsafeNativeMethods.DestroyWindow(System.Runtime.InteropServices.HandleRef hWnd) + 0x10 bytes 
    System.Windows.Forms.dll!System.Windows.Forms.NativeWindow.DestroyHandle() + 0x89 bytes 
    System.Windows.Forms.dll!System.Windows.Forms.Control.DestroyHandle() + 0x157 bytes 
    System.Windows.Forms.dll!System.Windows.Forms.Control.RecreateHandleCore() + 0x16a bytes    
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.RecreateHandleCore() + 0x1a bytes    
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.SetAutoComplete(bool reset, bool recreate) + 0x105 bytes 
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.ObjectCollection.ClearInternal() + 0xa1 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.ObjectCollection.Clear() + 0x17 bytes    
>   Echo.exe!Echo.Echo.UpdateCOMPortsComboBox() Line 231 + 0x1d bytes   C#
    [Native to Managed Transition]  
    mscorlib.dll!System.Delegate.DynamicInvokeImpl(object[] args) + 0x77 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbackDo(System.Windows.Forms.Control.ThreadMethodEntry tme) + 0xa7 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(object obj) + 0x90 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallback(System.Windows.Forms.Control.ThreadMethodEntry tme) + 0xa2 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbacks() + 0xda bytes   
    System.Windows.Forms.dll!System.Windows.Forms.Control.MarshaledInvoke(System.Windows.Forms.Control caller, System.Delegate method, object[] args, bool synchronous) + 0x365 bytes   
    System.Windows.Forms.dll!System.Windows.Forms.Control.Invoke(System.Delegate method, object[] args) + 0x50 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.Invoke(System.Delegate method) + 0x7 bytes    
    Echo.exe!Echo.Echo.WndProc(ref System.Windows.Forms.Message m) Line 247 + 0x19 bytes    C#
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.OnMessage(ref System.Windows.Forms.Message m) + 0x13 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.WndProc(ref System.Windows.Forms.Message m) + 0x31 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.NativeWindow.DebuggableCallback(System.IntPtr hWnd, int msg, System.IntPtr wparam, System.IntPtr lparam) + 0x64 bytes 
    [Native to Managed Transition]  
    [Managed to Native Transition]  
    System.Windows.Forms.dll!System.Windows.Forms.StringSource.Bind(System.Runtime.InteropServices.HandleRef edit, int options) + 0x46 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.SetAutoComplete(bool reset, bool recreate) + 0x2f4 bytes 
    System.Windows.Forms.dll!System.Windows.Forms.ComboBox.ObjectCollection.Add(object item) + 0x55 bytes   
    Echo.exe!Echo.Echo.UpdateCOMPortsComboBox() Line 237 + 0x34 bytes   C#
    [Native to Managed Transition]  
    mscorlib.dll!System.Delegate.DynamicInvokeImpl(object[] args) + 0x77 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbackDo(System.Windows.Forms.Control.ThreadMethodEntry tme) + 0xa7 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(object obj) + 0x90 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallback(System.Windows.Forms.Control.ThreadMethodEntry tme) + 0xa2 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.Control.InvokeMarshaledCallbacks() + 0xda bytes   
    System.Windows.Forms.dll!System.Windows.Forms.Control.MarshaledInvoke(System.Windows.Forms.Control caller, System.Delegate method, object[] args, bool synchronous) + 0x365 bytes   
    System.Windows.Forms.dll!System.Windows.Forms.Control.Invoke(System.Delegate method, object[] args) + 0x50 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.Invoke(System.Delegate method) + 0x7 bytes    
    Echo.exe!Echo.Echo.WndProc(ref System.Windows.Forms.Message m) Line 247 + 0x19 bytes    C#
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.OnMessage(ref System.Windows.Forms.Message m) + 0x13 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Control.ControlNativeWindow.WndProc(ref System.Windows.Forms.Message m) + 0x31 bytes  
    System.Windows.Forms.dll!System.Windows.Forms.NativeWindow.DebuggableCallback(System.IntPtr hWnd, int msg, System.IntPtr wparam, System.IntPtr lparam) + 0x64 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) + 0x1b8 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(int reason, System.Windows.Forms.ApplicationContext context) + 0x16c bytes  
    System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoop(int reason, System.Windows.Forms.ApplicationContext context) + 0x61 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Application.RunDialog(System.Windows.Forms.Form form) + 0x33 bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Form.ShowDialog(System.Windows.Forms.IWin32Window owner) + 0x38f bytes    
    System.Windows.Forms.dll!System.Windows.Forms.Form.ShowDialog() + 0x7 bytes 
    Echo.exe!Echo.Program.NewEcho() Line 48 + 0xa bytes C#
    mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x63 bytes   
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool ignoreSyncCtx) + 0xb0 bytes    
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x2c bytes    
    mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x44 bytes   
    [Native to Managed Transition]

我使用以下代码在单独的线程中创建新的终端窗口：

    public static void CreateNewEchoThread()
    {
        //// Create a new thread
        Thread  EchoThread      = new Thread(new ThreadStart(Program.NewEcho));

        // Set thread parameters
        EchoThread.IsBackground = true;
        EchoThread.SetApartmentState(ApartmentState.STA);

        //// Start the thread
        EchoThread.Start();

        // Increment the number of open Echo forms
        Echo.NumberOfOpenWindows++;
    }

    [STAThread]
    static void NewEcho()
    {
        // Create a new Echo form window and show it as a Dialog to prevent the thread from exiting immediately.
        Echo NewEchoForm    = new Echo();
        NewEchoForm.ShowDialog();
    }
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1 回答 1

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我找到了一种避免 RaceOnRCW 的方法。

我用一个一个一个地删除每个项目的循环替换 Clear 调用。不是我喜欢的解决方案，但它似乎有效。

我仍然想听听有关如何执行此操作的其他想法，因为我无法使用清除功能让我很困扰。

int NItems  = COMPortsComboBox.Items.Count;
for(int i = 0; i < NItems; i++)
{
    COMPortsComboBox.Items.RemoveAt(0);
}
于 2013-01-15T09:48:49.730 回答