	Skype:	TextControlSupport
	Orders:	877-462-4772

Drag and Drop Text in TX Text Control .NET

Author:	TX Text Control Support Department
Language:	Visual C#
Version:	1.0
Released:	November 12, 2007
Last modified:	January 11, 2008
Requirements:	TX Text Control .NET with Visual C#
Download code:	tx_text_tricks.zip [10.15 KB, ZIP]

Dragging and dropping text can be helpful to rearrange large portions of text. It is a very easy way to move text around in word processing applications.

TX Text Control provides all the events needed to implement this behavior. This sample uses 3 different events to control drag and drop: MouseDown, MouseUp and MouseMove.

On the MouseUp event, the selected text is stored in a separate Selection object that holds the currently selected text, it's character index start position and length.

private void textControl1_MouseUp(object sender, MouseEventArgs e)
{
  if (dragAction == false)
  {
    fillSyncSelection();
  }
  ...

private void fillSyncSelection()
{
  syncSelection.Start = textControl1.Selection.Start;
  syncSelection.Length = textControl1.Selection.Length;
  syncSelection.Text = textControl1.Selection.Text;
}

If the user clicks into the selected text, a boolean flag is activated. This flag indicates that a drag and drop action is currently being performed:

private void textControl1_MouseDown(object sender, MouseEventArgs e)
{
  if (syncSelection.Length > 0 && (textControl1.Selection.Start >=
      syncSelection.Start && textControl1.Selection.Start <=
      syncSelection.Start + syncSelection.Length))
  {
    dragAction = true;
    textControl1.CaretWidth = 2;
  }
}

In the MouseMove event, the input position is set to the current mouse position.

private void textControl1_MouseMove(object sender, MouseEventArgs e)
{
  if( dragAction == true)
  {
    textControl1.Selection.Length = 0;
    textControl1.InputPosition = new TXTextControl.InputPosition(new Point((e.X * DPIX) + 
                                 textControl1.ScrollLocation.X, (e.Y * DPIX) +
                                 textControl1.ScrollLocation.Y));
  }
}

When the mouse button is released again, the selected text is copied to the current input position and removed from the original position:

private void textControl1_MouseUp(object sender, MouseEventArgs e)
{
  ...
  else
  {
    int start = syncSelection.Start;
 
    if (textControl1.Selection.Start < syncSelection.Start)
    {
      start = syncSelection.Start + syncSelection.Text.Length;
    }
 
    textControl1.Selection.Text = syncSelection.Text;
    int inputPos = textControl1.Selection.Start;
    textControl1.Select(start, syncSelection.Length);
    textControl1.Selection.Text = "";
    textControl1.Selection.Start = inputPos;
    textControl1.CaretWidth = 1;
    syncSelection = new TXTextControl.Selection();
    dragAction = false;
  }
}

The minimum requirements for this sample application are TX Text Control .NET trial version and Visual Studio 2005.

top