C# - Moving a control to the mouse's position

问题

I am trying to get a control to follow the cursor when the user clicks and drag the control. The problem is that 1.) the control doesn't go to the mouse's position, and 2.) the control flickers and flies all over the place. I've tried a few different methods of doing this, but all so far have failed.

I've tried:

protected override void OnMouseDown(MouseEventArgs e)
{
     while (e.Button == System.Windows.Forms.MouseButtons.Left)
     {
          this.Location = e.Location;
     }
}

and

protected override void OnMouseMove(MouseEventArgs e)
{
     while (e.Button == System.Windows.Forms.MouseButtons.Left)
     {
          this.Location = e.Location;
      }
}

but neither of these work. Any help is appreciated, and thanks in advance!

回答1:

Here's how to do it:

private Point _Offset = Point.Empty;

protected override void MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        _Offset = new Point(e.X, e.Y);
    }
}

protected override void MouseMove(object sender, MouseEventArgs e)
{
    if (_Offset != Point.Empty)
    {
        Point newlocation = this.Location;
        newlocation.X += e.X - _Offset.X;
        newlocation.Y += e.Y - _Offset.Y;
        this.Location = newlocation; 
    }
}

protected override void MouseUp(object sender, MouseEventArgs e)
{
    _Offset = Point.Empty;
}

_Offset is used here for two purposes: keeping track of where the mouse was on the control when you initially clicked it, and also keeping track of whether the mouse button is down or not (so that the control doesn't get dragged when the mouse cursor goes over it and the button isn't down).

You definitely don't want to switch the ifs in this code to whiles, as it will make a difference.

回答2:

there are mistakes in the answer 1 1.Set mouse handlers to control ,not to form like button1_MouseMove 2.do not use this vector,but your control instead(Point newlocation = button1.Location;) 3.you do not need to override handlers.

in my test after these changes button(or other control) moves fine.

Chigook

回答3:

Try this to move the object according to the mouse's position and the code below given is to gather the mouse's move path and the location saved in the arraylist to obtain the path where mouse point is moving. You have to declare the arraylist globally.

private void panel1_MouseMove(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        ArrayList inList = new ArrayList();
        inList.Add(e.X);
        inList.Add(e.Y);
        list.Add(inList);
    }
}

When the user clicks the button the control has to move in the path that the user dragged in the screen

private void button1_Click_2(object sender, EventArgs e)
{
    foreach (ArrayList li in list)
    {
        pic_trans.Visible = true;
        pic_trans.Location = new Point(Convert.ToInt32(li[0]), Convert.ToInt32(li[1]));
        pic_trans.Show();
    }
}

回答4:

private Point ptMouseDown=new Point();

protected override void MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        ptMouseDown = new Point(e.X, e.Y);
    }
}

protected override void MouseMove(object sender, MouseEventArgs e)
{
    if (_Offset != Point.Empty)
    {
        Pointf[] ptArr=new Pointf[]{this.Location};
        Point Diff=new Point(e.X-ptMouseDown.X,e.Y-ptMouseDown.Y);
        Matrix mat=new Matrix();
        mat.Translate(Diff.X,Diff.Y);
        mat.TransFromPoints(ptArr);
        this.Location=ptArr[0];
    }
}   

protected override void MouseUp(object sender, MouseEventArgs e)
{
    _Offset = Point.Empty;
}

来源：https://stackoverflow.com/questions/2703132/c-sharp-moving-a-control-to-the-mouses-position

标签

controls

mouse

position

flicker