鼠标滚轮事件（C＃）

时间：2009-01-26 10:03:07

标签： c# winforms mousewheel

我无法在主窗体中获取鼠标滚轮事件。

作为演示，我提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中得到了鼠标滚轮事件但没有Form1任何想法？

干杯，

詹姆斯

8 个答案:

答案 0 :(得分：38)

我怀疑只要鼠标悬停在面板上，即使面板没有焦点，OP也希望获得滚动事件。

此处解释了实现此行为的方法：

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

在这里：

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

从链接论坛获取的代码片段之一：

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);
  }
}

此代码将基本拦截所有wm_mousewheel事件，并将它们重定向到鼠标当前悬停的控件。面板不再需要具有焦点来接收车轮事件。

答案 1 :(得分：16)

你的问题来自于form1具有焦点，而不是panel1。 ...哪个方面意味着将触发form1的事件，而不是panel1的事件。

我使用对Form1中构造函数的以下更改重新创建了您的场景，并验证它是否会触发滚轮事件。

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);
    }
}

答案 2 :(得分：12)

添加面板MouseEnter的另一个事件，并在其回调函数中获取输入焦点：

void MouseEnterEvent()
{
   this.Panel.Focus();
}

答案 3 :(得分：3)

感谢@nitrogenycs的回答，我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，你只需要从这个类继承你的Form而不是Form，因为你需要MouseWheel管理的每个表单＆＃34;：

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）。

答案 4 :(得分：0)

也许这对你有用吗？

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);
    }
}

答案 5 :(得分：0)

我认为你有点误解了我的问题。在我的主要表单上使用以下代码我不会收到MouseWheel事件：

public Form1()
    {
        InitializeComponent();

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

但我确实得到了这个事件：

public Form1()
    {
        InitializeComponent();
        this.MouseWheel += new MouseEventHandler(panel1_MouseWheel);

    }

我希望在没有Form2混淆的情况下更清楚。我只是试图以我的主要形式在Panel上获取MouseWheel事件。

干杯，

詹姆斯

答案 6 :(得分：0)

面板本身不具有焦点，只有放置在面板内的项目才能具有焦点。只有在内部放置了一些东西并且该东西具有焦点时，该面板才会收到MouseWheel事件。只需在面板上方移动并移动鼠标滚轮，即可将事件发送到表单，而不是面板。

这是两个例子之间的区别。

答案 7 :(得分：-1)

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
                }
            }
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