判断鼠标是否位于表单上方的最佳方法是什么？

Question

我想出了如何捕获鼠标点击 覆盖整个表单，但此方法对于 MouseEnter 和 MouseLeave 的转换效果不佳。我的表单布局由许多 Panels 和 TableLayoutPanels 组成，因此没有可以监视事件的包罗万象的控件，显然还有一个 MouseLeave 事件按钮并不意味着光标离开了整个表单。有没有人想出一个好方法来解决这个问题？

Answer 1

正如有人指出此处可以使用 SetWindowsHookEx() 或只是连接MouseMove 事件到窗体中的所有控件上。后者对我来说效果很好。唯一的缺点是，如果您在运行时添加/删除控件，您可能需要另一个解决方案。

using System;
using System.Drawing;
using System.Windows.Forms;

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

            MouseMove += OnMouseMove;
            MouseLeave += OnMouseLeave;

            HookMouseMove(this.Controls);
        }

        private void HookMouseMove(Control.ControlCollection ctls)
        {
            foreach (Control ctl in ctls)
            {
                ctl.MouseMove += OnMouseMove;
                HookMouseMove(ctl.Controls);
            }
        }

        private void OnMouseMove(object sender, MouseEventArgs e)
        {
            BackColor = Color.Plum;

            Control ctl = sender as Control;
            if (ctl != null)
            {
                // Map mouse coordinate to form
                Point loc = this.PointToClient(ctl.PointToScreen(e.Location));
                Console.WriteLine("Mouse at {0},{1}", loc.X, loc.Y);
            }
        }

        private void OnMouseLeave(object sender, EventArgs e)
        {
            BackColor = Color.Gray;
        }

    }
}

Answer 2

在表单中添加一个计时器，并设置合理的时间间隔（可能是 50 毫秒）。在 Tick 事件处理程序中使用此代码来查看鼠标是否位于表单上：

// Check if mouse is currently over the form
    bool temp_mof = ClientRectangle.Contains(
       Form.MousePosition.X - Location.X,
       Form.MousePosition.Y - Location.Y);

编辑：这是一个更完整的解决方案，用于检测鼠标位于表单上并且已单击按钮。 timer1Tick() 是表单上计时器的 Tick 事件处理程序。表单上的其他控件不需要额外的事件处理程序。这将使您的表单成为“一个巨大的按钮”:)

bool m_mouse_over_form = false;
// Assume the left button is down at onset
bool m_left_button_down = true;

void timer1Tick (object sender, EventArgs e)
{
   // Check if mouse is currently over the form
   bool temp_mof = ClientRectangle.Contains(
      Form.MousePosition.X - Location.X,
      Form.MousePosition.Y - Location.Y);

   // were we already over the form before this tick?
   if (temp_mof && m_mouse_over_form)
   {
       // we need to detect the mouse down and up to avoid
       // repeated calls if the mouse button is held down for more
       // than our Tick interval

       // was the mouse button up prior to now?
       if (!m_left_button_down)
       {
           // is the button down now?
           m_left_button_down = (MouseButtons == MouseButtons.Left);

           if (m_left_button_down)
           {
               // the button was down and has now been released
               LeftButtonClickHandler();
           }
           else
           {
               // do nothing, the button has not been release yet
           }
       }
       else
       {
           // update the button state
           m_left_button_down = (MouseButtons == MouseButtons.Left);
       }
   }
   else if (temp_mof)
   {
       // the mouse just entered the form

       m_mouse_over_form = true;

       // set the initial state of the left button
       m_left_button_down = MouseButtons == MouseButtons.Left);
   }
   else
   {
       // the mouse is not currently over the form
       m_mouse_over_form = false;
       m_left_button_down = true;
   }
}

Answer 3

在表单和表单控件上执行 MouseEnter 和 MouseLeave 事件；使用布尔值来确定鼠标是进入还是离开。

一个例子是

    private static bool mouseEnteredForm

    private void Form1_MouseMove(object sender, MouseEventArgs e)
    {
        mouseEnteredForm = true;
        Form.MouseLeave += Form1_MouseLeave;
        CheckMouseLocation();
    }

    private void Form1_MouseLeave(object sender, MouseEventArgs e)
    {
        mouseEnteredForm = false
        CheckMouseLocation();
    }

    private static void CheckMouseLocation()
    {
        if(!mouseOverForm)
        {
            MessageBox.Show("Mouse Not Over Form!);
        }
        else if(mouseOverForm) //else if is optional. You could also use else in this case. I used else if for the sake of the example.
        {
            MessageBox.Show("Mouse Is Over Form");
        }
    }

如果表单上有很多对象，这可能会变得乏味

Answer 4

首先检查 ClientRectangle 是否 包含当前鼠标位置。例如，在您的 MouseMove 处理程序，您可以：

if (ClientRectangle.Contains(e.Location))
{
    bool mouseIsOverThisControl = true;
}

Answer 5

我找到了一些接近我想要的答案，但我最终做了一些不同的事情。我想检测鼠标是否离开表单区域（包括标题栏），这对我有用：

在表单构造函数中，我添加一个计时器：

time.Interval = 250;
time.Tick += time_Tick;
time.Start();

然后在 tick 方法中，我执行以下操作：

void time_Tick(object sender, EventArgs e)
{
    switch (RectangleToScreen(Bounds).Contains(PointToScreen(Cursor.Position))) {
        case true:
            if (Opacity != .9999D)
                Opacity = .9999D;
            break;
        case false:
            if (Opacity != .5D)
                Opacity = .5D;
            break;
    }
}