WPF

ascotravel wrote:

i will create a system to knows how many Users are connected to the Application(via Database )

derm2 wrote:

I had to do it in a rather unelegant way because of this:

- Save the mouse location on previewmousedwn
- Compare this to the mouse position previewmousemove. If it's different and the button is still clicked, then find the child item for the originally clicked position, and do the dragdrop for it.

derm2 wrote:

fired practically randomly

Mark Salsbery
Microsoft MVP - Visual C++

derm2 wrote:

Starting your mousemove eventhandler with "if the mouse has moved" feels unelegant for me

derm2 wrote:

I have never worked with a framework that fired mousemove events without the mouse moving before WPF.

<Grid >
    <Canvas >
        <TextBlock x:Name="textBlock" Text="0" Foreground="Black" />
        <Rectangle Canvas.Left="30" Canvas.Top="30" Width="50" Height="50"
                             Stroke="Red" StrokeThickness="2" Fill="#00000000"
                             MouseLeftButtonDown="Rectangle_MouseLeftButtonDown"
                             MouseLeftButtonUp="Rectangle_MouseLeftButtonUp"
                             MouseMove="Rectangle_MouseMove" />
    </Canvas>
</Grid>

Point anchorPoint;
Point currentPoint;
bool isInDrag = false;
int moveCount = 0;

private void Rectangle_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    FrameworkElement element = sender as FrameworkElement;
    anchorPoint = e.GetPosition(null);
    element.CaptureMouse();
    isInDrag = true;
    e.Handled = true;
}

private void Rectangle_MouseMove(object sender, MouseEventArgs e)
{
    moveCount++;
    textBlock.Text = moveCount.ToString();

    if (isInDrag)
    {
        FrameworkElement element = sender as FrameworkElement;
        currentPoint = e.GetPosition(null);
        double x = System.Convert.ToDouble(element.GetValue(Canvas.LeftProperty));
        double y = System.Convert.ToDouble(element.GetValue(Canvas.TopProperty));
        element.SetValue(Canvas.LeftProperty, x + currentPoint.X - anchorPoint.X);
        element.SetValue(Canvas.TopProperty, y + currentPoint.Y - anchorPoint.Y);
        anchorPoint = currentPoint;
    }
}

private void Rectangle_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    if (isInDrag)
    {
        FrameworkElement element = sender as FrameworkElement;
        element.ReleaseMouseCapture();
        isInDrag = false;
        e.Handled = true;
    }
}

Mark Salsbery
Microsoft MVP - Visual C++

class Tree2 : TreeView
	{

		public Tree2()
		{
			TreeViewItem root = new TreeViewItem();
			root.Header = "root";
			TreeViewItem child = new TreeViewItem();
			root.Items.Add(child);
			this.Items.Add(root);
			this.PreviewMouseDown += new MouseButtonEventHandler(Tree2_PreviewMouseDown);
			this.PreviewMouseMove += new MouseEventHandler(Tree2_PreviewMouseMove);
		}
		Point lastMouseDown;
		bool readyToDrag = false;

		void Tree2_PreviewMouseDown(object sender, MouseButtonEventArgs e)
		{
			lastMouseDown = e.GetPosition(this);
			readyToDrag = true;
		}

		void Tree2_PreviewMouseMove(object sender, MouseEventArgs e)
		{
			Point currentPosition = e.GetPosition(this);

			if (readyToDrag)
			{
				if (currentPosition == lastMouseDown)
				{
					throw new Exception("This is a mousemove event fired for a mouseclick");
				}
				else
				{
					//do the DragDrop here
				}
			}
		}
	}

derm2 wrote:

Put this onto your form, and expand the root node. Mousemove will be fired, and you will start a drag operation if you don't check the position.

void Tree2_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    // Note this may not work as desired if you have TreeView(s) embedded in your TreeView :)

    TreeView tv = e.Source as TreeView;
    if (tv != null)
    {
        lastMouseDown = e.GetPosition(this);
        readyToDrag = true;
    }
}

Mark Salsbery
Microsoft MVP - Visual C++