c#: “System.InvalidOperationException: 队列为空”使用 SendKey.SendWait() 时出现和其他错误

Question

我编写了一个程序来将“Enter”键发送到某个活动窗口。我使用计时器来获取当前活动窗口的标题并采取相应的操作。我制作了一个错误日志文件，以便我可以跟踪所有错误。以下是产生错误的代码：

    private static void OnTimedEvent(object source, ElapsedEventArgs e)
    {
        try
        {
            ttl = GetActiveWindowTitle();
            if (ttl != null)
            {
                if (ttl.ToLower() == "xxxxxxxxxxx")
                {
                    SendKeys.SendWait("{ENTER}");
                }
            }
        }
        catch (Exception err)
        {
            Write2ErrLog(err, "OnTimedEvent");
        }
    }

这是 GetActiveWindowTitle() 方法。

    static private string GetActiveWindowTitle()
    {
        try
        {
            const int nChars = 256;
            IntPtr handle = IntPtr.Zero;
            StringBuilder Buff = new StringBuilder(nChars);
            handle = GetForegroundWindow();

            if (GetWindowText(handle, Buff, nChars) > 0)
            {
                return Buff.ToString();
            }
            return null;
        }
        catch (Exception e)
        {
            Write2ErrLog(e, "GetActiveWindowTitle");
            return null;
        }
    }

以下是我收到的错误：

4/19/2011 12:57:16 PM: System.InvalidOperationException: Queue empty.
   at System.Collections.Queue.Dequeue()
   at System.Windows.Forms.SendKeys.SendInput(Byte[] oldKeyboardState, Queue previousEvents)
   at System.Windows.Forms.SendKeys.Send(String keys, Control control, Boolean wait)
   at System.Windows.Forms.SendKeys.SendWait(String keys)
   at DataViews_SendKeys.Form1.OnTimedEvent(Object source, ElapsedEventArgs e)  OnTimedEvent

4/19/2011 1:03:11 PM: System.ArgumentException: Destination array was not long enough. Check destIndex and length, and the array's lower bounds.
   at System.Array.Copy(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length, Boolean reliable)
   at System.Collections.Queue.Clone()
   at System.Windows.Forms.SendKeys.Send(String keys, Control control, Boolean wait)
   at System.Windows.Forms.SendKeys.SendWait(String keys)
   at DataViews_SendKeys.Form1.OnTimedEvent(Object source, ElapsedEventArgs e)  OnTimedEvent

4/19/2011 1:04:00 PM: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Windows.Forms.UnsafeNativeMethods.PeekMessage(MSG& msg, HandleRef hwnd, Int32 msgMin, Int32 msgMax, Int32 remove)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.SendKeys.Flush()
   at System.Windows.Forms.SendKeys.Send(String keys, Control control, Boolean wait)
   at System.Windows.Forms.SendKeys.SendWait(String keys)
   at DataViews_SendKeys.Form1.OnTimedEvent(Object source, ElapsedEventArgs e)  OnTimedEvent

我应该提到的是，我运行此程序的计算机是带有 Intel Xeon 处理器的 HP 服务器计算机，操作系统是 Windows XP。该程序在我的笔记本电脑上运行没有错误，但在服务器计算机上则不然。有什么想法吗？

Answer 1

这可能是由于您的服务器上启用了 UAC，而不是您的桌面上启用的。我在使用 SendKeys.Send() 时遇到了相同的行为。

另一件事是要检查您正在构建的 .NET 版本。请参阅 SendKeys 发送被阻止。