问题
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
回答1:
A working solution:
Register for
MouseWheel
event of your form andDropDownClosed
event of your rootMenuStripItem
(here, rootItem) in theLoad
event of the formthis.MouseWheel += Form3_MouseWheel; rootItem.DropDownOpened += rootItem_DropDownOpened; rootItem.DropDownClosed += rootItem_DropDownClosed;
Add the code for
Keyboard
class which simulate key pressespublic 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); } }
Add the code for
DropDownOpened
,DropDownClosed
,MouseWheel
events:bool IsMenuStripOpen = false; void rootItem_DropDownOpened(object sender, EventArgs e) { IsMenuStripOpen = true; } void rootItem_DropDownClosed(object sender, EventArgs e) { IsMenuStripOpen = false; } void Form3_MouseWheel(object sender, MouseEventArgs e) { if (IsMenuStripOpen) { if (e.Delta > 0) { Keyboard.KeyUp(); } else { Keyboard.KeyDown(); } } }
回答2:
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);
}
}
回答3:
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}" );
}
}
回答4:
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.
来源:https://stackoverflow.com/questions/13139074/mouse-wheel-scrolling-toolstrip-menu-items