[英]Mouse wheel event to work with hovered control
在我的C#3.5 Windows窗體應用程序中,我有一些SplitContainers。 每個內部都有一個列表控件(dock fill)。 當焦點位於其中一個控件上並移動鼠標滾輪時,滾動顯示現在聚焦的列表。
我的任務是滾動列表,該列表當前是鼠標懸停的,而不是選中的列表。 是否可以在Windows窗體中? 如果沒有,是否可以使用PInvoke?
看起來你可以使用IMessageFilter
和PInvoke來處理這個問題。 可以在將鼠標滾輪事件重定向到未聚焦的Windows窗體控件中找到VB中的示例。 您應該能夠輕松地將其轉換為C#。
興趣點
此類對給定任務使用以下技術:
使用VB.NET到C#轉換器 ,這是你最終得到的:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.Windows.Forms;
using System.Runtime.InteropServices;
public class MouseWheelRedirector : IMessageFilter
{
private static MouseWheelRedirector instance = null;
private static bool _active = false;
public static bool Active
{
get { return _active; }
set
{
if (_active != value)
{
_active = value;
if (_active)
{
if (instance == null)
{
instance = new MouseWheelRedirector();
}
Application.AddMessageFilter(instance);
}
else
{
if (instance != null)
{
Application.RemoveMessageFilter(instance);
}
}
}
}
}
public static void Attach(Control control)
{
if (!_active)
Active = true;
control.MouseEnter += instance.ControlMouseEnter;
control.MouseLeave += instance.ControlMouseLeaveOrDisposed;
control.Disposed += instance.ControlMouseLeaveOrDisposed;
}
public static void Detach(Control control)
{
if (instance == null)
return;
control.MouseEnter -= instance.ControlMouseEnter;
control.MouseLeave -= instance.ControlMouseLeaveOrDisposed;
control.Disposed -= instance.ControlMouseLeaveOrDisposed;
if (object.ReferenceEquals(instance.currentControl, control))
instance.currentControl = null;
}
private MouseWheelRedirector()
{
}
private Control currentControl;
private void ControlMouseEnter(object sender, System.EventArgs e)
{
var control = (Control)sender;
if (!control.Focused)
{
currentControl = control;
}
else
{
currentControl = null;
}
}
private void ControlMouseLeaveOrDisposed(object sender, System.EventArgs e)
{
if (object.ReferenceEquals(currentControl, sender))
{
currentControl = null;
}
}
private const int WM_MOUSEWHEEL = 0x20a;
public bool PreFilterMessage(ref System.Windows.Forms.Message m)
{
if (currentControl != null && m.Msg == WM_MOUSEWHEEL)
{
SendMessage(currentControl.Handle, m.Msg, m.WParam, m.LParam);
return true;
}
else
{
return false;
}
}
[DllImport("user32.dll", SetLastError = false)]
private static extern IntPtr SendMessage(
IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);
}
我有類似的問題,並找到了這個帖子......所以發布我的遲來的答案給其他可能找到這個帖子的人。 在我的情況下,我只是希望鼠標滾輪事件轉到光標下的任何控件...就像右鍵單擊一樣(如果右鍵單擊轉到焦點控件而不是光標下的控件,那將會很困惑...我認為鼠標輪也是如此,除了我們已經習慣了它。
無論如何,答案非常簡單。 只需將PreFilterMessage添加到您的應用程序中,並將鼠標滾輪事件重定向到鼠標下的控件:
public bool PreFilterMessage(ref Message m)
{
switch (m.Msg)
{
case WM_MOUSEWHEEL: // 0x020A
case WM_MOUSEHWHEEL: // 0x020E
IntPtr hControlUnderMouse = WindowFromPoint(new Point((int)m.LParam));
if (hControlUnderMouse == m.HWnd)
return false; // already headed for the right control
else
{
// redirect the message to the control under the mouse
SendMessage(hControlUnderMouse, m.Msg, m.WParam, m.LParam);
return true;
}
default:
return false;
}
}
使用Control.MouseEnter Event將焦點設置為控件。 例如,使用ActiveControl屬性
這是布朗肯尼迪的回答與漢克舒爾茨的評論:
首先,你應該讓一個類實現IMessageFilter :
public class MessageFilter : IMessageFilter
{
private const int WM_MOUSEWHEEL = 0x020A;
private const int WM_MOUSEHWHEEL = 0x020E;
[DllImport("user32.dll")]
static extern IntPtr WindowFromPoint(Point p);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
public bool PreFilterMessage(ref Message m)
{
switch (m.Msg)
{
case WM_MOUSEWHEEL:
case WM_MOUSEHWHEEL:
IntPtr hControlUnderMouse = WindowFromPoint(new Point((int)m.LParam));
if (hControlUnderMouse == m.HWnd)
{
//Do nothing because it's already headed for the right control
return false;
}
else
{
//Send the scroll message to the control under the mouse
uint u = Convert.ToUInt32(m.Msg);
SendMessage(hControlUnderMouse, u, m.WParam, m.LParam);
return true;
}
default:
return false;
}
}
}
用法示例:
public partial class MyForm : Form
{
MessageFilter mf = null;
private void MyForm_Load(object sender, EventArgs e)
{
mf= new MessageFilter();
Application.AddMessageFilter(mf);
}
private void MyForm_FormClosing(object sender, FormClosingEventArgs e)
{
Application.RemoveMessageFilter(mf);
}
}
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