Mouse wheel scrolling Toolstrip menu items

Question

I have some menus that contain many menuitems. Mouse wheel doesn\'t scroll them. I have to use the keyboard arrows or click the arrows at top and bottom. Is it possible to u

Answer 1

I modified Mohsen Afshin's answer to click the up/down arrows instead of sending up/down key presses. My application had a ContextMenuStrip called menu. Here's the code.

In the initialization:

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

The ScrollMenu function:

[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;
}

I was having trouble getting the mouse_event function to click a specific location, so I moved the cursor, clicked, and then moved the cursor back. It doesn't seem the cleanest, but it works.