父控件鼠标进入/离开具有子控件的事件

经过更多的研究,我发现 Application.AddMessageFilter method . 使用这个,我创建了一个.NET版本的鼠标挂钩:

class MouseMessageFilter : IMessageFilter, IDisposable
{
    public MouseMessageFilter()
    {
    }

    public void Dispose()
    {
        StopFiltering();
    }

    #region IMessageFilter Members

    public bool PreFilterMessage(ref Message m)
    {
         // Call the appropriate event
         return false;
    }

    #endregion

    #region Events

    public class CancelMouseEventArgs : MouseEventArgs
    {...}

    public delegate void CancelMouseEventHandler(object source, CancelMouseEventArgs e);
    public event CancelMouseEventHandler MouseMove;
    public event CancelMouseEventHandler MouseDown;
    public event CancelMouseEventHandler MouseUp;

    public void StartFiltering()
    {
        StopFiltering();
        Application.AddMessageFilter(this);
    }

    public void StopFiltering()
    {
        Application.RemoveMessageFilter(this);
    }
}

然后,我可以在容器控件中处理mousemove事件,检查鼠标是否在父控件中,然后开始工作。(我还必须跟踪上一个鼠标悬停在父控件上的情况,以便停止先前启动的父控件。)

------编辑

在我的窗体类中,我创建并连接筛选器:

public class MyForm : Form
{
   MouseMessageFilter msgFilter;

   public MyForm()
   {...
       msgFilter = new MouseMessageFilter();
       msgFilter.MouseDown += new MouseMessageFilter.CancelMouseEventHandler(msgFilter_MouseDown);
       msgFilter.MouseMove += new MouseMessageFilter.CancelMouseEventHandler(msgFilter_MouseMove);
    }

    private void msgFilter_MouseMove(object source, MouseMessageFilter.CancelMouseEventArgs e)
    {
        if (CheckSomething(e.Control)
            e.Cancel = true;
    }   
}

我觉得我找到了一个比目前公认的顶级解决方案更好的解决方案。

其他建议的解决方案的问题是,它们要么相当复杂(直接处理较低级别的消息)。

或者,它们会在角情况下失败:如果鼠标直接从子控件内部转到容器外部,则依赖鼠标在mouseleave上的位置可能会导致错过鼠标退出。

虽然此解决方案并不完全优雅,但它非常简单且有效:

添加一个透明控件,该控件占用要接收MouseEnter和MouseSave事件的容器的整个空间。

我在Amed的回答中发现了一个很好的透明控制: Making a control transparent

然后我把它简化为:

public class TranspCtrl : Control
{
    public TranspCtrl()
    {
        SetStyle(ControlStyles.SupportsTransparentBackColor, true);
        SetStyle(ControlStyles.Opaque, true);
        this.BackColor = Color.Transparent;
    }

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.ExStyle = cp.ExStyle | 0x20;
            return cp;
        }
    }
}

示例用法:

public class ChangeBackgroundOnMouseEnterAndLeave
{
    public Panel Container;
    public Label FirstLabel;
    public Label SecondLabel;

    public ChangeBackgroundOnMouseEnterAndLeave()
    {
        Container = new Panel();
        Container.Size = new Size(200, 60);

        FirstLabel = new Label();
        FirstLabel.Text = "First Label";
        FirstLabel.Top = 5;

        SecondLabel = new Label();
        SecondLabel.Text = "Second Lable";
        SecondLabel.Top = 30;

        FirstLabel.Parent = Container;
        SecondLabel.Parent = Container;

        Container.BackColor = Color.Teal;

        var transparentControl = new TranspCtrl();
        transparentControl.Size = Container.Size;

        transparentControl.MouseEnter += MouseEntered;
        transparentControl.MouseLeave += MouseLeft;

        transparentControl.Parent = Container;
        transparentControl.BringToFront();
    }

    void MouseLeft(object sender, EventArgs e)
    {
        Container.BackColor = Color.Teal;
    }

    void MouseEntered(object sender, EventArgs e)
    {
        Container.BackColor = Color.Pink;
    }
}

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

        var test = new ChangeBackgroundOnMouseEnterAndLeave();
        test.Container.Top = 20;
        test.Container.Left = 20;
        test.Container.Parent = this;
    }
}

享受适当的mouseleave和mouseenter活动!

您可以像这样找出鼠标是否在控件的边界内(假定此代码驻留在容器控件中;如果不在,则替换 this 引用容器控件时):

private void MyControl_MouseLeave(object sender, EventArgs e)
{
    if (this.ClientRectangle.Contains(this.PointToClient(Cursor.Position)))
    {
        // the mouse is inside the control bounds
    }
    else
    {
        // the mouse is outside the control bounds
    }
}

我认为你不需要挂信息泵来解决这个问题。用户界面中的一些标记应该可以做到这一点。我认为您在控制类中创建了一个成员变量,类似于control-someparent,当调用一个onMouseEnter处理程序时,它将引用父控件。然后,在onmouseleave中,检查someparent“标志”的值,如果它与当前发件人的值相同,则不要实际停止处理,只需返回即可。只有当父级不同时,您才会停止并将ousomeParent重置为空。

我也有同样的需求。保罗·威廉姆斯的回答为我提供了核心思想,但我很难理解代码。我又找到了一个 here 两个例子一起帮助我开发了自己的版本。

要初始化,请将感兴趣的容器控件传递到 ContainerMessageFilter 构造函数。类收集容器的窗口句柄及其内的所有子控件。

然后,在操作期间,类过滤 WM_MOUSEMOVE 消息,检查消息的 HWnd 以确定鼠标在其中移动的控件。通过这种方式,它可以确定鼠标何时在所监视的容器内的控件集内或之外移动。

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

public class ContainerMessageFilter : IMessageFilter {
    private const int WM_MOUSEMOVE = 0x0200;

    public event EventHandler MouseEnter;
    public event EventHandler MouseLeave;

    private bool insideContainer;
    private readonly IEnumerable<IntPtr> handles;

    public ContainerMessageFilter( Control container ) {
        handles = CollectContainerHandles( container );
    }

    private static IEnumerable<IntPtr> CollectContainerHandles( Control container ) {
        var handles = new List<IntPtr> { container.Handle };

        RecurseControls( container.Controls, handles );

        return handles;
    }

    private static void RecurseControls( IEnumerable controls, List<IntPtr> handles ) {
        foreach ( Control control in controls ) {
            handles.Add( control.Handle );

            RecurseControls( control.Controls, handles );
        }
    }

    public bool PreFilterMessage( ref Message m ) {
        if ( m.Msg == WM_MOUSEMOVE ) {
            if ( handles.Contains( m.HWnd ) ) {
                // Mouse is inside container
                if ( !insideContainer ) {
                    // was out, now in
                    insideContainer = true;
                    OnMouseEnter( EventArgs.Empty );
                }
            }
            else {
                // Mouse is outside container
                if ( insideContainer ) {
                    // was in, now out
                    insideContainer = false;
                    OnMouseLeave( EventArgs.Empty );
                }
            }
        }

        return false;
    }

    protected virtual void OnMouseEnter( EventArgs e ) {
        var handler = MouseEnter;
        handler?.Invoke( this, e );
    }

    protected virtual void OnMouseLeave( EventArgs e ) {
        var handler = MouseLeave;
        handler?.Invoke( this, e );
    }
}

在下面的使用示例中,我们希望监视鼠标的进入和退出 Panel 子控件包含:

public partial class Form1 : Form {
    private readonly ContainerMessageFilter containerMessageFilter;

    public Form1() {
        InitializeComponent();

        containerMessageFilter = new ContainerMessageFilter( panel1 );
        containerMessageFilter.MouseEnter += ContainerMessageFilter_MouseEnter;
        containerMessageFilter.MouseLeave += ContainerMessageFilter_MouseLeave;
        Application.AddMessageFilter( containerMessageFilter );
    }

    private static void ContainerMessageFilter_MouseLeave( object sender, EventArgs e ) {
        Console.WriteLine( "Leave" );
    }

    private static void ContainerMessageFilter_MouseEnter( object sender, EventArgs e ) {
        Console.WriteLine( "Enter" );
    }

    private void Form1_FormClosed( object sender, FormClosedEventArgs e ) {
        Application.RemoveMessageFilter( containerMessageFilter );
    }
}