/// <summary>
/// Handles the mouse left button down click event
/// </summary>
/// <param name="e"></param>
protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
{
base.OnPreviewMouseLeftButtonDown(e);
if (!e.Source.Equals(this)) // do drag if the source is the DragCanvas
{
isDown = true; // mouse is down, save the click point
startpoint = e.GetPosition(this);
// if an element clicked or a child of the element is clicked and has the IsDraggable property the proceed
VisualTreeHelper.HitTest((UIElement)e.Source, new HitTestFilterCallback(MyHitTestFilter), new HitTestResultCallback(MyHitTestResult), new PointHitTestParameters(e.GetPosition((UIElement)e.Source)));
if (isdrag)
{
// if the element is a MwiChild then stop, otherwise find if the element has a parent type of MwiChild
if (e.Source.GetType().Equals(typeof(AnalysisChild)))
{
originalElement = (UIElement)e.Source;
}
else
{
originalElement = (UIElement)VisualTreeSearch.FindByParentType((UIElement)e.Source, typeof(AnalysisChild));
}
if (originalElement != null)
{
int zindex = Canvas.GetZIndex(originalElement); // set the s-index of the element
((AnalysisChild)originalElement).IsSelected = true; // select the element because is was clicked
this.CaptureMouse(); // capture the mouse
e.Handled = true; // handle the event
}
}
}
}
/// <summary>
/// Drag the element about the Canvas by updating its Canavas position.
/// </summary>
/// <param name="currentPosition"></param>
private void DragMoved(Point currentPosition)
{
double elementLeft = (currentPosition.X - startpoint.X) + originalLeft;
double elementTop = (currentPosition.Y - startpoint.Y) + originalTop;
// Find the panel under the drag canavas and get its size. This way items can be dragged over
// the minimized child elements
DockPanel panel = (DockPanel)VisualTreeSearch.FindByParentType(this, typeof(DockPanel));
Size panelSize = this.RenderSize;
if (panel != null)
{
panelSize = panel.RenderSize;
}
// make sure the element is within the bounds of the DragCanvas
if (elementLeft < 0)
{
elementLeft = 0;
}
else if ((elementLeft + originalElement.RenderSize.Width) > panelSize.Width)
{
elementLeft = panelSize.Width - originalElement.RenderSize.Width;
}
Canvas.SetLeft(originalElement, elementLeft);
// make sure the element is within the bounds of the DragCanvas
if (elementTop < 0)
{
elementTop = 0;
}
else if ((elementTop + originalElement.RenderSize.Height) > panelSize.Height)
{
elementTop = panelSize.Height - originalElement.RenderSize.Height;
}
Canvas.SetTop(originalElement, elementTop);
}