28

我无法在主窗体中获取鼠标滚轮事件。

作为一个演示，我想出了一个简单的例子：

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        this.panel1.MouseWheel += new MouseEventHandler(panel1_MouseWheel);
        this.panel1.MouseMove += new MouseEventHandler(panel1_MouseWheel);

        Form2 f2 = new Form2();
        f2.Show(this);
    }

    private void panel1_MouseWheel(object sender, MouseEventArgs e)
    {
        if(e.Delta != 0)
        Console.Out.WriteLine(e.Delta);
    }
}

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();

        this.MouseMove += new MouseEventHandler(Form2_MouseMove);
        this.MouseWheel += new MouseEventHandler(Form2_MouseMove);
    }

    private void Form2_MouseMove(object sender, MouseEventArgs e)
    {
        if(e.Delta != 0)
            Console.Out.WriteLine(e.Delta);
    }
}

我在 Form2 中得到鼠标滚轮事件，但在 Form1 中没有任何想法？

干杯，

詹姆士

4

7 回答 7

41

我怀疑当面板没有焦点时，只有鼠标悬停在面板上时，OP 想要获取滚动事件。

此处解释了一种完成此行为的方法：

http://social.msdn.microsoft.com/forums/en-US/winforms/thread/eb922ed2-1036-41ca-bd15-49daed7b637c/

和这里：

http://social.msdn.microsoft.com/forums/en-US/winforms/thread/6bfb9287-986d-4c60-bbcc-23486e239384/

取自链接论坛的代码片段之一：

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsApplication1 {
  public partial class Form1 : Form, IMessageFilter {
    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) {
          SendMessage(hWnd, m.Msg, m.WParam, m.LParam);
          return true;
        }
      }
      return false;
    }

    // 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);
  }
}

这段代码基本上会拦截所有 wm_mousewheel 事件并将它们重定向到鼠标当前悬停的控件。面板不再需要获得焦点来接收滚轮事件。

于 2012-04-04T07:42:30.597 回答
18

您的问题源于 form1 有焦点，而不是 panel1。...这当然意味着将触发 form1 的事件，而不是 panel1 的事件。

我重新创建了您的场景，并对 Form1 中的构造函数进行了以下更改，并验证它触发了滚轮事件。

public Form1()
{
        InitializeComponent(); 

        /*  --- Old code that don't work ---
            this.panel1.MouseWheel += new MouseEventHandler(panel1_MouseWheel);
            this.panel1.MouseMove += new MouseEventHandler(panel1_MouseWheel);
        */

        this.MouseWheel += new MouseEventHandler(panel1_MouseWheel);
        this.MouseMove += new MouseEventHandler(panel1_MouseWheel);

        Form2 f2 = new Form2();
        f2.Show(this);
    }
}
于 2009-01-26T10:31:42.047 回答
12

添加另一个面板事件，MouseEnter并在其回调函数中获取输入焦点：

void MouseEnterEvent()
{
   this.Panel.Focus();
}
于 2009-03-05T07:13:31.420 回答
4

感谢@nitrogenycs 的回答，我编写了一个简单的通用类来轻松解决这个问题：

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Drawing;

namespace MyNamespace
{
  public class MouseWheelManagedForm : Form, IMessageFilter
  {
    private bool managed;

    public MouseWheelManagedForm () : this (true) {
   }

    public MouseWheelManagedForm (bool start) {
      managed = false;
      if (start)
        ManagedMouseWheelStart();
    }

    protected override void Dispose (bool disposing) {
      if (disposing)
        ManagedMouseWheelStop();
      base.Dispose(disposing);
    }

    /************************************
     * IMessageFilter implementation
     * *********************************/
    private const int WM_MOUSEWHEEL = 0x20a;
    // 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);

    private bool IsChild (Control ctrl) {
      Control loopCtrl = ctrl;

      while (loopCtrl != null && loopCtrl != this)
        loopCtrl = loopCtrl.Parent;

      return (loopCtrl == this);
    }

    public bool PreFilterMessage (ref Message m) {
      if (m.Msg == WM_MOUSEWHEEL) {
        //Ensure the message was sent to a child of the current form
        if (IsChild(Control.FromHandle(m.HWnd))) {
          // Find the control at screen position m.LParam
          Point pos = new Point(m.LParam.ToInt32() & 0xffff, m.LParam.ToInt32() >> 16);

          //Ensure control under the mouse is valid and is not the target control
          //otherwise we'd be trap in a loop.
          IntPtr hWnd = WindowFromPoint(pos);
          if (hWnd != IntPtr.Zero && hWnd != m.HWnd && Control.FromHandle(hWnd) != null) {
            SendMessage(hWnd, m.Msg, m.WParam, m.LParam);
            return true;
          }
        }
      }
      return false;
    }

    /****************************************
     * MouseWheelManagedForm specific methods
     * **************************************/
    public void ManagedMouseWheelStart () {
      if (!managed) {
        managed = true;
        Application.AddMessageFilter(this);
      }
    }

    public void ManagedMouseWheelStop () {
      if (managed) {
        managed = false;
        Application.RemoveMessageFilter(this);
      }
    }

  }
}

从那里，您只需要从此类继承您的 Form 而不是 Form 对于您需要“管理” MouseWheel 的每个表单：

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Windows.Forms;

namespace MyApp
{
  public partial class MyForm : MyNamespace.MouseWheelManagedForm
  {
    public MyForm ()
    {
      InitializeComponent();
    }

  }
}

希望这会帮助别人（比我）。

于 2014-06-05T18:09:39.843 回答
0

也许这对你有用？

public partial class Form1 : Form {
    public Form1() {
        InitializeComponent();
        Form2 f2 = new Form2();
        f2.MouseWheel += new MouseEventHandler(panel1_MouseWheel);
        f2.MouseMove += new MouseEventHandler(panel1_MouseWheel);
        f2.Show(this);
    }

    private void panel1_MouseWheel(object sender, MouseEventArgs e)
    {
        if(e.Delta != 0) Console.Out.WriteLine(e.Delta);
    }
}
于 2009-01-26T10:13:45.843 回答
0

面板本身不能拥有焦点，只有放置在面板内的项目才能拥有焦点。只有在其中放置了某些东西并且该东西具有焦点时，面板才会收到 MouseWheel 事件。只需将鼠标悬停在面板上并移动鼠标滚轮即可将事件发送到表单，而不是面板。

这是您的两个示例之间的区别。

于 2009-01-26T10:31:56.930 回答
-2 
this.MouseWheel += pictureBox1_MouseWheel; //tanımlama
void pictureBox1_MouseWheel(object sender, MouseEventArgs e)
            {
                if (Convert.ToString(e.Delta) == "120")
                {
                    //yukarı
                }
                else if (Convert.ToString(e.Delta) == "-120")
                {
                    //aşağı
                }
            }
于 2017-08-14T20:22:27.003 回答