[.NET]让Panel对Mouse滚轮事件(Wheel)有感觉，而且能触发Scroll事件

Posted 2022-11-04 petewell

之前有写了一篇“让Panel对Mouse滚轮事件(Wheel)有感觉”，是透过 SendMessage 的方式去叫 Panel Scroll。
但是却不会触发Panel的Scroll事件。那怎么办呢?

在之前有写了一篇“让Panel对Mouse滚轮事件(Wheel)有感觉”，是透过 SendMessage 的方式去叫 Panel Scroll。

但是却不会触发Panel的Scroll事件。那怎么办呢?

所以我们可以透过Control.FromHandle来取到那个控件，然后再触发该控件的Scroll事件，如下，

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1

    public partial class Form1 : Form, IMessageFilter
    

        // P/Invoke declarations
        [DllImport("user32.dll")]
        private static extern IntPtr WindowFromPoint(Point pt);

        [DllImport("user32.dll")]
        private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp);

        public Form1()
        
            InitializeComponent();
            Application.AddMessageFilter(this);
        

        public bool PreFilterMessage(ref Message m)
        
            if (m.Msg == 0x20a)
            
                // WM_MOUSEWHEEL, find the control at screen position m.LParam
                Point pos = new Point(m.LParam.ToInt32() & 0xffff, m.LParam.ToInt32() >> 16);
                IntPtr hWnd = WindowFromPoint(pos);
                if (hWnd != IntPtr.Zero && hWnd != m.HWnd && Control.FromHandle(hWnd) != null)
                
                    //取得控件
                    ScrollableControl ctrl = Control.FromHandle(hWnd) as ScrollableControl;
                    int orgValue = 0;
                    if (ctrl != null)
                    
                        //取得控件垂直ScrollBar的值
                        orgValue = ctrl.VerticalScroll.Value;
                    
                    SendMessage(hWnd, m.Msg, m.WParam, m.LParam);
                    if (ctrl != null)
                    
                        //取得控件垂直ScrollBar的值
                        int newValue = ctrl.VerticalScroll.Value;
                        var se = new ScrollEventArgs(ScrollEventType.ThumbTrack, orgValue, newValue
                            , ScrollOrientation.VerticalScroll);
                        FireScrollEvent(ctrl, se);
                    
                    return true;
                
            
            return false;
        

        /// 

        /// 触发控件的Scroll事件
        /// 
        /// 
        /// 
        private void FireScrollEvent(ScrollableControl sc, ScrollEventArgs e)
        
            MethodInfo onScroll = sc.GetType().GetMethod("OnScroll",
                System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
            onScroll.Invoke(sc, new object[]  e );
        
    

参考数据

让Panel对Mouse滚轮事件(Wheel)有感觉

Control.FromHandle

WinForms: How to programatically fire an event handler?

原文:大专栏  [.NET]让Panel对Mouse滚轮事件(Wheel)有感觉，而且能触发Scroll事件