need help with drag and drop of control

[jiggsroger]

Hello folks,

I have a panel on a form with several other controls on it. The panel has to be a totally draggable over the form - and stop at that. Draggable only over the form! This is how I have implemented the drag and drop currently (see code block below). I need to ensure that the draggable panel doesn't tread beyond the form area irrespective of the form's size. I tried meddling with the height, location et all but then either it stops scrolling or doesn't come inside the form when i click.

can you please tell me how to ensure that the whole panel stays within the form(that is not even the corners go out of form)?

private void myDock_MouseUp(object sender, MouseEventArgs e)
        {
            isDragging = false;
            Invalidate();
        }

        private void myDock_MouseDown(object sender, MouseEventArgs e)
        {
            isDragging = true;
            clickOffsetX = e.X;
            clickOffsetY = e.Y;
            this.Invalidate();
           
           
        }

        private void myDock_MouseMove(object sender, MouseEventArgs e)
        {
            if (isDragging == true)
            {
                myDock.Left = e.X + myDock.Left - clickOffsetX;
                myDock.Top = e.Y + myDock.Top - clickOffsetY;
                this.Invalidate();

               
            }

            Invalidate();
        }

Hoping for a solution,
-
Roger

[Xav]

Try an "if" statement to check whether the panel is out of the bounding rectangle of the form.

[jiggsroger]

Hi Xav,
the if is ok, i cant figure wat to put in the if()!!

[Xav]

Hmm... try drawing a diagram, to help you see. You might need for different conditions:

1. if the left side is touching the left side of the form.
2. if the top side is touching the top side of the form.
3. if the bottom side is touching the bottom side of the form.
4. work out the last one yourself...

Try and work a condition that uses these four.

Xav

[jiggsroger]

Xav, this is wat i was trying but it totally locks my movement.

if ((myDock.Left > this.Left) && (myDock.Top > this.Top) && (myDock.Bottom < this.Bottom) && (myDock.Right < this.Right))

myDock is the panel and 'this' the form..

i dunno if i am using the wrong properties to check the perimeter..
could use more help..

thanks in advance,
Roger

[Xav]

Ah... now I see the problem. You are using the boolean comparison operator "&&" (AND). At the moment, this is what it says in English...

If the left side is touching the left side AND the right side is touching the right side AND the top side is touching the top side AND the bottom side is touching the bottom side (ALL at the same time!) then lock movement.

You see the problem? You need to use the operator OR, which in C# is not "&&", but "||". Try it with this - make your program halt dragging if any one of the conditions is met (i.e. if any borders are being hit).

[jiggsroger]

Hi again,

if((myDock.Left > this.Left) || (myDock.Top < this.Top) || (myDock.Bottom < this.Bottom) || (myDock.Right < this.Right))

did this but it doesnt prevent the pane from going out of boundary. what properties else do i look for?

[Xav]

Maybe the properties are wrong. What do "left", "right", "top" and "bottom" mean? Think about it logically - you want something like "if the right hand side of the panel is off the edge of the form, then cut movement."

[jiggsroger]

Hey Xav!
Got it! and it woiks!

Thanks Mate!
Roger

[Xav]

You're welcome!