getting mouse position of different control

问题

I have a panel (panel2) inside another panel (panel1). I want to get mouse position of panel1, but when I move my mouse over panel2, the following code stops working.

    private void panel1_MouseMove(object sender, MouseEventArgs e)
    {
        label1.Text = "Offset: " + e.X + " x " + e.Y;
    }

How can I get it to read the mouse arguments, even if the mouse is over panel2? Thanks!

EDIT: panel2 is located at center x=100, y=100 of panel1. if I move my mouse on panel2 left top corner it gives me coordinates for example 1x1, where I need to location on panel1 like 101x101

EDIT 2: I'm not trying to drag it, just read the coordinates of original panel (panel1) so I can calculate the offset for zooming the panel2. So I only need mousemove, nothing else. Thanks

回答1:

If you only need to do this while a mouse button is being held down (for example, because you are tracking a drag and drop operation or a selection) then you can do the following:

In your MouseDown handler, call this.Capture = true;
Now your MouseMove handler will receive mouse move messages even when the mouse is over another control.
In your MouseUp handler, call this.Capture = false; - Note: If you forget to do this, your other controls in the same process will not receive any mouse messages.

Other than that, it's very tricky to get MouseMove messages from other controls without adding mouse handlers to those other controls.

The main thing about this.Capture is that you need a good time to set it to true and another good time to set it back to false. Generally, that's done in MouseDown and MouseUp as I described.

However, you could also convert the coords from Panel2-relative to Panel1-relative like so:

Convert from Panel2 coords to screen coords:

Point screenCoords = panel2.PointToScreen(mouseCoordInPanel2);

Then convert from screen coords to Panel1-relative coords:

Point mouseCoordInPanel1 = panel1.PointToClient(screenCoords);

To do this you would have to have a MouseMove handler in Panel2 where you did this conversion, and Panel2 would need a reference to Panel1 in order to call panel1.PointToClient()

回答2:

You must also assign to the event of the other panel.

回答3:

can't you put the event handler in panel2, then use the left/top properties of panel1 and panel2 to offset the mouse position within panel2 to get your desired location in panel1?

回答4:

I also think that assigning an event to the second panel would be the best thing. When the mouse is on Panel 1, the coordinates would be provided directly; when it is on Panel 2, they would be converted by accounting for the relative positions between both panels (pretty straightforward: variation in X/Y positions; values which do not need to be hardcoded but updated at runtime).

来源：https://stackoverflow.com/questions/17088991/getting-mouse-position-of-different-control

标签

mousemove