.NET: How to check if the mouse is in a control?

Question

i want to know if the mouse is in a particular control in .NET

private void panel1_MouseLeave(object sender, EventArgs e)
{
   if (MouseIsInControl((Control)         


        

Answer 1

I also use a System.Windows.Forms.Timer for this solution, but I don't use the enter/leave mouse events anymore. They have caused me too much grief. Instead I use the MouseMove event on the component I need to know the mouse is over. I have 2 member variables named in this class.

bool Hovering = false;
System.Drawing.Point LastKnownMousePoint = new System.Drawing.Point();

In my case, I wanted to toggle a border around a label. I deal with knowing if the mouse is over the label control I care about as follows:

    private void label1_MouseMove(object sender, MouseEventArgs e)
    {
        // Mouse Position relative to the form... not the control
        LastKnownMousePoint = Cursor.Position; 

        label1.BorderStyle = BorderStyle.Fixed3D;
        timer1.Stop();
        timer1.Interval = 50; // Very fast (Overkill?  :) )
        timer1.Start();
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
        System.Drawing.Point point = Cursor.Position;
        if (LastKnownMousePoint.Equals(point))
        {
            // If the mouse is somewhere on the label, I'll call that Hovering.  
            // Though not technically the MS definition, it works for me.
            Hovering = true;
        }
        else if (Hovering == false)
        {
            label1.BorderStyle = BorderStyle.None;
            timer1.Stop();
        }
        else
        {
            Hovering = false;
            // Next time the timer ticks, I'll stop the timer and
            // Toggle the border.
        }
    }

This works because I only update the LastKnownMousePoint when the mouse is over the control (a label in this case). So, if the mouse moves outside of the control, I won't update LastKnownMousePoint and I'll know it's time to toggle the border style.

Answer 2

This Hans Passant Answer can be adapted to do what you want:

private bool mEntered;
private Timer timer1;

public Form1() {
  InitializeComponent();

  timer1 = new Timer();
  timer1.Interval = 200;
  timer1.Tick += timer1_Tick;
  timer1.Enabled = false;
}

private void panel1_MouseEnter(object sender, EventArgs e) {
  timer1.Enabled = true;
}

private void timer1_Tick(object sender, EventArgs e) {
  bool entered = panel1.ClientRectangle.Contains(panel1.PointToClient(Cursor.Position));
  if (entered != mEntered) {
    mEntered = entered;
    if (!entered) {
      timer1.Enabled = false;
      // OK, Do something, the mouse left the parent container
    }
  }
}

Answer 3

No hooks or subclassing needed.

private bool MouseIsOverControl(Button btn) => 
    btn.ClientRectangle.Contains(btn.PointToClient(Cursor.Position))

This method also works if the mouse is outside of the form containing the control. It uses a button object but you can use any UI class

You can test the method easily like so:

private void button1_Click(object sender, EventArgs e)
{
    // Sleep to allow you time to move the mouse off the button
    System.Threading.Thread.Sleep(900); 

    // Try moving mouse around or keeping it over the button for different results
    if (MouseIsOverControl(button1))
         MessageBox.Show("Mouse is over the button.");
    else MessageBox.Show("Mouse is NOT over the button.");
}