當菜單欄打開時，MouseEnter事件不會觸發

Question

我有一個menuStrip，其中有幾個項目，並且在窗體的其他部分有一個按鈕。當鼠標進入按鈕時，它執行一些操作（MouseEnter事件）。我遇到的問題是，當菜單欄被打開時，如果鼠標進入按鈕，MouseEnter事件不會被觸發。菜單欄打開時有什麼方法可以啓動嗎？

要以圖形方式看到這一點，這就是I'm做：

我有一個MenuStrip中，併爲每個父菜單項，有一個按鈕。該按鈕將位於其上方，因此菜單欄中唯一可見的部分將是帶有其子項的容器。

現在，當鼠標進入按鈕時，例如「系統」，它會在菜單項中執行一次單擊。這就是容器出現的原因。但一旦打開，如果我想打開其他父母的其他容器，我必須先點擊才能失去焦點。然後，我想要達到的目的就是在不點擊的情況下做到這一點。

我想要的行爲就像menutrip所具有的行爲。例如，如果打開系統，鼠標進入客戶端，它會自動關閉系統並打開客戶端。

Answer 1

讓我們來看看這是否是一個有效的答案：

#region IMessageFilter implementation 
/// <summary> Redirect WM_MouseWheel messages to window under mouse.</summary> 
    /// <remarks>Redirect WM_MouseWheel messages to window under mouse (rather than 
/// that with focus) with adjusted delta. 
/// <see cref="http://www.flounder.com/virtual_screen_coordinates.htm"/> 
/// Dont forget to add this to constructor: 
///    Application.AddMessageFilter(this); 
///</remarks> 
    /// <param name="m">The Windows Message to filter and/or process.</param> 
    /// <returns>Success (true) or failure (false) to OS.</returns> 
    [System.Security.Permissions.PermissionSetAttribute(
     System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
    bool IMessageFilter.PreFilterMessage(ref Message m) { 
     // Determine window and control at these coordinates. 
    //var pos = WindowsMouseInput.GetPointLParam(m.LParam); 
     var hWnd = WindowFromPoint(WindowsMouseInput.GetPointLParam(m.LParam)); 
     var ctl = Control.FromHandle(hWnd); 
    if (hWnd != IntPtr.Zero && hWnd != m.HWnd && ctl != null) { 
    switch(m.Msg) { 
     default: return false; 
     case (int)WM.MOUSEWHEEL: 
     DebugTracing.Trace(TraceFlag.ScrollEvents, true," - {0}.WM.MouseWheel: {1}", 
                Host.Name, ((WM)m.Msg).ToString()); 
     if (ctl is MapPanel) { 
      var keyState = WindowsMouseInput.GetKeyStateWParam(m.WParam); 
      var mult   = keyState.HasFlag(MouseKeys.Control) ? 5 : 1; 
      keyState   = keyState &= ~MouseKeys.Control; 
      var wheelDelta = WindowsMouseInput.WheelDelta(m.WParam); 
      // forward delta of +/- 30 instead of +/- 120; 30/120 == 1/4 
      var newWparam = WindowsMouseInput.WParam((Int16)(mult*wheelDelta/4), keyState); 
      SendMessage(hWnd, m.Msg, newWparam, m.LParam); 
      return true; 
     } else if (ctl is MapFormOverview) { 
      var keyState = WindowsMouseInput.GetKeyStateWParam(m.WParam); 
      var wheelDelta = WindowsMouseInput.WheelDelta(m.WParam); 
      // forward delta of +/- 54 instead of +/- 120 
      // 54 = 3 * 18 (default point height in pixels?); 54/120 == 9/20 
      var newWparam = WindowsMouseInput.WParam((Int16)(wheelDelta*9/20), keyState); 
      SendMessage(hWnd, m.Msg, newWparam, m.LParam); 
      return true; 
     } 
     break; 
    } 
    } 
    return false; 
    } 
#region Extern declarations 
/// <summary>P/Invoke declaration for user32.dll.WindowFromPoint</summary> 
    /// <remarks><see cref="http://msdn.microsoft.com/en-us/library/windows/desktop/ms633558(v=vs.85).aspx"/></remarks> 
    /// <param name="pt">(Sign-extended) screen coordinates as a Point structure.</param> 
    /// <returns>Window handle (hWnd).</returns> 
    [DllImport("user32.dll")] 
    private static extern IntPtr WindowFromPoint(Point pt); 
    /// <summary>P/Invoke declaration for user32.dll.SendMessage</summary> 
    /// <param name="hWnd">Window handle</param> 
    /// <param name="msg">Windows message</param> 
    /// <param name="wp">WParam</param> 
    /// <param name="lp">LParam</param> 
    /// <returns></returns> 
    [DllImport("user32.dll", CharSet = CharSet.Auto)] 
    private static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam); 
#endregion 
#endregion 

你會希望像that..key機，功能鍵等哪種類型的火災