Drag and Drop question

2 replies. Latest Post by StephenL on May 18, 2007.

(1)

Member

14 points

Drag and Drop question

05-17-2007 5:53 PM |

I am implementing drag and drop to allow the user to drag around a custom control and while it almost works, if the user moves to quickly, the mouse goes off my control and I stop getting mouse move events. My current work around is to end the drag on mouse leave but I would much rather not have the mouse run away. Does anybody have any ideas? My code is below.

Thanks

Stephen

private void mousePressed(object sender, EventArgs args)

{

MouseEventArgs mea = args as MouseEventArgs;

if (mea != null)

{

oldLoc = mea.GetPosition(null); isDragging = true;

}

private void mouseReleased(object sender, EventArgs args)

{

isDragging = false;

}

// Hack since we dont get mouseMoved if user goes to quick and leaves us behind

// better would be to still get mouse events somehow

private void mouseLeft(object sender, EventArgs args)

{

isDragging = false;

}

private void mouseMoved(object sender, EventArgs args)

{

if (! isDragging)

return;

MouseEventArgs mea = args as MouseEventArgs; if (mea != null)

{

Point newLoc = mea.GetPosition(null);

double xOffset = newLoc.X - oldLoc.X;

double yOffset = newLoc.Y - oldLoc.Y;

mainCanvas.SetValue(Canvas.TopProperty, (double)mainCanvas.GetValue(Canvas.TopProperty) + yOffset); mainCanvas.SetValue(Canvas.LeftProperty, (double)mainCanvas.GetValue(Canvas.LeftProperty) + xOffset);

oldLoc = newLoc;

}

Mark Rid...

Contributor

2357 points

273 Posts

Re: Drag and Drop question

05-18-2007 2:28 PM |

You need to capture the mouse in your MouseLeftButtonDown event handler:

sender.CaptureMouse();

And to be a good citizen you should call releaseMouseCapture. Check out this MSDN article on implementing Drag and drop: http://msdn2.microsoft.com/en-us/library/bb190645.aspx

-mark
Program Manager
Microsoft
This post is provided "as-is"

StephenL

Member

14 points

12 Posts

Re: Drag and Drop question

05-18-2007 3:19 PM |

Thanks, Mark. I did see the javascript example before posting my question but when actually coding it in C# I mistakenly tried calling CaptureMouse on the framework element returned from InitializeFromXaml instead of on the sender. That just made things worse.

Stephen

Unanswered Question
Answered Question
Announcement

Microsoft Silverlight

Drag and Drop question

Drag and Drop question

Re: Drag and Drop question

Re: Drag and Drop question