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 use the mouse wheel to scroll toolstrip menu items? Thanks
Mouse wheel scrolling Toolstrip menu items
5.9k Views Asked by Jerry At
4
There are 4 best solutions below
7

You can enable it application wide with this class:
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);
}
}
0

This is very simply using a submenu (ToolStripMenuItem
) of the context menu :
Assuming using a form1
(or UserControl
) and a 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}" );
}
}
0

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.
A working solution:
Register for
MouseWheel
event of your form andDropDownClosed
event of your rootMenuStripItem
(here, rootItem) in theLoad
event of the formAdd the code for
Keyboard
class which simulate key pressesAdd the code for
DropDownOpened
,DropDownClosed
,MouseWheel
events: