Swapping controls in TableLayoutPanel

[mce]

Hi,

Basically I want to be able to drag drop controls inside the table layout panel where the control in the cell where i drop to swap position with the control where i drag from. I already managed to do the drag and drop part, but it doesn't swap position!

I have the table layout panel created using the form designer and the cells populated with checkbox controls (which i also created using the form designer). I want to be able to drag and drop the checkbox controls (swapping the controls by doing so) within the table layout panel cells during runtime, just like what i am able to do using the form designer during design time. I already managed to drag and drop controls within the table layout panel, But my problem now is when i drag and drop a control over another cell, the original checkbox control in the cell doesn't swap position with control i am dragging over.


This is what i did inside the DrapDrop function.

 private void tableLayoutPanel1_DragDrop(object sender, DragEventArgs e)
        {

            CheckBox cb = e.Data.GetData(typeof(CheckBox)) as CheckBox;


            Point loc = this.tableLayoutPanel1.PointToClient(new Point(e.X, e.Y));

            //detemine the cell location

            int ColumnIndex = -1;

            int RowIndex = -1;

            int x = 0;

            int y = 0;
          
            
            while (ColumnIndex <= this.tableLayoutPanel1.ColumnCount)
            {

                if (loc.X < x)
                {

                    break;

                }

                ColumnIndex++;

                x += this.tableLayoutPanel1.GetColumnWidths()[ColumnIndex];

            }

            while (RowIndex <= this.tableLayoutPanel1.RowCount)
            {

                if (loc.Y < y)
                {

                    break;

                }

                RowIndex++;

                y += this.tableLayoutPanel1.GetRowHeights()[RowIndex];

            }
          
            this.tableLayoutPanel1.Controls.Add(cb, ColumnIndex, RowIndex);

            //cb.Invalidate();
        }

[mce]

anyone?


I have the following piece of codes now; but i just don't understand why it doesn't work!!!

Could anyone point out why it doesn't work correctly? The cell position i got is wrong sometimes, but not always. why is this so??

        int _orginRow = -1;
        int _orginCol = -1;
        private void tableLayoutPanel1_DragEnter(object sender, DragEventArgs e)
        {
            CheckBox cb = e.Data.GetData(typeof(CheckBox)) as CheckBox;

            e.Effect = DragDropEffects.Move;
            Point loc = this.tableLayoutPanel1.PointToClient(new Point(e.X, e.Y));

            int ColumnIndex = -1;
            int RowIndex = -1;
            int x = 0;
            int y = 0;

            while (ColumnIndex <= this.tableLayoutPanel1.ColumnCount)
            {

                if (loc.X < x)
                {

                    break;

                }

                ColumnIndex++;

                x += this.tableLayoutPanel1.GetColumnWidths()[ColumnIndex];

            }

            while (RowIndex <= this.tableLayoutPanel1.RowCount)
            {

                if (loc.Y < y)
                {

                    break;

                }

                RowIndex++;

                y += this.tableLayoutPanel1.GetRowHeights()[RowIndex];

            }
            _orginCol = ColumnIndex;
            _orginRow = RowIndex;

        }


private void tableLayoutPanel1_DragDrop(object sender, DragEventArgs e)
        {
      
            CheckBox cb = e.Data.GetData(typeof(CheckBox)) as CheckBox;


            Point loc = this.tableLayoutPanel1.PointToClient(new Point(e.X, e.Y));

            //detemine the cell location

            int ColumnIndex = -1;

            int RowIndex = -1;

            int x = 0;

            int y = 0;
           
            
            while (ColumnIndex <= this.tableLayoutPanel1.ColumnCount)
            {

                if (loc.X < x)
                {

                    break;

                }

                ColumnIndex++;

                x += this.tableLayoutPanel1.GetColumnWidths()[ColumnIndex];

            }

            while (RowIndex <= this.tableLayoutPanel1.RowCount)
            {

                if (loc.Y < y)
                {

                    break;

                }

                RowIndex++;

                y += this.tableLayoutPanel1.GetRowHeights()[RowIndex];

            }

            Control l_control = this.tableLayoutPanel1.GetControlFromPosition(ColumnIndex, RowIndex);
            this.tableLayoutPanel1.Controls.Remove(l_control);
            this.tableLayoutPanel1.Controls.Remove(cb);


            this.tableLayoutPanel1.Controls.Add(l_control, _orginCol, _orginRow);
            this.tableLayoutPanel1.Controls.Add(cb, ColumnIndex, RowIndex);

        }

[rliq]

What about, rather than catching the drag/drop in the table panel, you catch the drag/drop of the individual controls within the table panel?

I think from a control you can find out what cell it is in, else derive your control and keep it's x,y up to date, eg:

public class DragableCheckBox : CheckBox
{
    Point _point(); // x,y of this CheckBox in the TableLayoutControl

    ...

    // DragDrop handler etc...
}

// somewhere else...

public List<DragableCheckBox> _dragableCheckBoxes;  

// possibly keep this sorted by Y aseceending, then X ascending, so that you can more easily
// repopulate the TableLayoutControl when required by simply iterating through this list and adding
//  them to the TableLayoutControl

When you drop, you can swap the x and y's of the two DragableCheckBox's and then (in a worst case scenario) repaint the whole of the TableLayoutPanel again by clearing it and adding the DragableCheckBox's again. If it's a small TableLayoutPanel, this may suffice, especially if you enable the DubbleBuffered property on the Main form...

Having said all of that, I do find that dynamically adding/removing items from a TableLayoutControl can be a bit painful as it does seem to assume a lot!!