Question

我有一些包含许多菜单项的菜单。鼠标滚轮不会滚动它们。我必须使用键盘箭头或单击顶部和底部的箭头。是否可以使用鼠标滚轮滚动工具条菜单项？感谢

Answer 1

工作解决方案：

在表单的MouseWheel事件中注册您的表单的DropDownClosed事件以及您的根MenuStripItem的{{1}}事件（此处为rootItem）
```
Load
```
添加模拟按键的this.MouseWheel += Form3_MouseWheel; rootItem.DropDownOpened += rootItem_DropDownOpened; rootItem.DropDownClosed += rootItem_DropDownClosed;类的代码
```
Keyboard
```
添加public static class Keyboard { [DllImport("user32.dll")] static extern uint keybd_event(byte bVk, byte bScan, int dwFlags, int dwExtraInfo); const byte VK_UP = 0x26; // Arrow Up key const byte VK_DOWN = 0x28; // Arrow Down key const int KEYEVENTF_EXTENDEDKEY = 0x0001; //Key down flag, the key is going to be pressed const int KEYEVENTF_KEYUP = 0x0002; //Key up flag, the key is going to be released public static void KeyDown() { keybd_event(VK_DOWN, 0, KEYEVENTF_EXTENDEDKEY, 0); keybd_event(VK_DOWN, 0, KEYEVENTF_KEYUP, 0); } public static void KeyUp() { keybd_event(VK_UP, 0, KEYEVENTF_EXTENDEDKEY, 0); keybd_event(VK_UP, 0, KEYEVENTF_KEYUP, 0); } }，DropDownOpened，DropDownClosed个事件的代码：
```
MouseWheel
```

Answer 2

您可以使用此类在应用程序范围内启用它：

public class DropDownMenuScrollWheelHandler : System.Windows.Forms.IMessageFilter
{
    private static DropDownMenuScrollWheelHandler Instance;
    public static void Enable(bool enabled)
    {
        if (enabled)
        {
            if (Instance == null)
            {
                Instance = new DropDownMenuScrollWheelHandler();
                Application.AddMessageFilter(Instance);
            }
        }
        else
        {
            if (Instance != null)
            {
                Application.RemoveMessageFilter(Instance);
                Instance = null;
            }
        }
    }
    private IntPtr activeHwnd;
    private ToolStripDropDown activeMenu;

    public bool PreFilterMessage(ref Message m)
    {
        if (m.Msg == 0x200 && activeHwnd != m.HWnd) // WM_MOUSEMOVE
        {
            activeHwnd = m.HWnd;
            this.activeMenu = Control.FromHandle(m.HWnd) as ToolStripDropDown;
        }
        else if (m.Msg == 0x20A && this.activeMenu != null) // WM_MOUSEWHEEL
        {
            int delta = (short)(ushort)(((uint)(ulong)m.WParam) >> 16);
            handleDelta(this.activeMenu, delta);
            return true;
        }
        return false;
    }

    private static readonly Action<ToolStrip, int> ScrollInternal
        = (Action<ToolStrip, int>)Delegate.CreateDelegate(typeof(Action<ToolStrip, int>),
            typeof(ToolStrip).GetMethod("ScrollInternal",
                System.Reflection.BindingFlags.NonPublic
                | System.Reflection.BindingFlags.Instance));

    private void handleDelta(ToolStripDropDown ts, int delta)
    {
        if (ts.Items.Count == 0)
            return;
        var firstItem = ts.Items[0];
        var lastItem = ts.Items[ts.Items.Count - 1];
        if (lastItem.Bounds.Bottom < ts.Height && firstItem.Bounds.Top > 0)
            return;
        delta = delta / -4;
        if (delta < 0 && firstItem.Bounds.Top - delta > 9)
        {
            delta = firstItem.Bounds.Top - 9;
        }
        else if (delta > 0 && delta > lastItem.Bounds.Bottom - ts.Height + 9)
        {
            delta = lastItem.Bounds.Bottom - owner.Height + 9;
        }
        if (delta != 0)
            ScrollInternal(ts, delta);
    }
}

Answer 3

这非常简单地使用上下文菜单的子菜单（ToolStripMenuItem）：

假设使用form1（或UserControl）和contextMenuStrip1：

private void form1_Load( object sender , EventArgs e )
{
    //this.MouseWheel -= When_MouseWheel;
    this.MouseWheel += When_MouseWheel;
}
void When_MouseWheel( object sender , MouseEventArgs e )
{
    if ( this.contextMenuStrip1.IsDropDown ) {
         //this.Focus();
         if ( e.Delta > 0 ) SendKeys.SendWait( "{UP}" );
         else SendKeys.SendWait( "{DOWN}" );         
    }
}

Answer 4

我修改了Mohsen Afshin的答案，单击向上/向下箭头而不是向上/向下按键发送。我的应用程序有ContextMenuStrip名为menu。这是代码。

在初始化中：

    menu.VisibleChanged += (s, e) =>
    {
        if (menu.Visible)
        {
            MouseWheel += ScrollMenu;
            menu.MouseWheel += ScrollMenu;
        }
        else
        {
            MouseWheel -= ScrollMenu;
            menu.MouseWheel -= ScrollMenu;
        }
    };

ScrollMenu功能：

[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern void mouse_event(uint dwFlags, uint dx, uint dy, uint cButtons, uint dwExtraInfo);

private void ScrollMenu(object sender, MouseEventArgs e)
{
    Point origin = Cursor.Position;
    int clicks;

    if (e.Delta < 0)
    {
        Cursor.Position = menu.PointToScreen(new Point(menu.DisplayRectangle.Left + 5, menu.DisplayRectangle.Bottom + 5));
        clicks = e.Delta / -40;
    }
    else
    {
        Cursor.Position = menu.PointToScreen(new Point(menu.DisplayRectangle.Left + 5, menu.DisplayRectangle.Top - 5));
        clicks = e.Delta / 40;
    }

    for (int i = 0; i < clicks; i++)
        mouse_event(0x0006, 0, 0, 0, 0);//Left mouse button up and down on cursor position
    Cursor.Position = origin;
}

我无法让mouse_event函数单击特定位置，因此我移动光标，单击，然后将光标移回。它似乎不是最干净的，但它确实有效。

鼠标滚轮滚动Toolstrip菜单项

4 个答案: