/// <summary>
/// Event raised when the user starts to drag a connector.
/// </summary>
private void ExecutionConnectorItem_DragStarted(object source, ExecutionConnectorItemDragStartedEventArgs e)
{
this.Focus();
e.Handled = true;
this.IsDragging = true;
this.IsNotDragging = false;
this.IsDraggingExecutionConnection = true;
this.IsNotDraggingExecutionConnection = false;
this.draggedOutExecutionConnectorItem = (ExecutionConnectorItem)e.OriginalSource;
var nodeItem = this.draggedOutExecutionConnectorItem.ParentNodeItem;
this.draggedOutNodeDataContext = nodeItem.DataContext != null ? nodeItem.DataContext : nodeItem;
this.draggedOutExecutionConnectorDataContext = this.draggedOutExecutionConnectorItem.DataContext != null ? this.draggedOutExecutionConnectorItem.DataContext : this.draggedOutExecutionConnectorItem;
//
// Raise an event so that application code can create a connection and
// add it to the view-model.
//
ExecutionConnectionDragStartedEventArgs eventArgs = new ExecutionConnectionDragStartedEventArgs(ExecutionConnectionDragStartedEvent, this, this.draggedOutNodeDataContext, this.draggedOutExecutionConnectorDataContext);
RaiseEvent(eventArgs);
//
// Retrieve the the view-model object for the connection was created by application code.
//
this.draggingExecutionConnectionDataContext = eventArgs.ExecutionConnection;
if (draggingExecutionConnectionDataContext == null)
{
//
// Application code didn't create any connection.
//
e.Cancel = true;
return;
}
}
/// <summary>
/// The mouse cursor has been moved.
/// </summary>
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (isDragging)
{
//
// Raise the event to notify that dragging is in progress.
//
Point curMousePoint = e.GetPosition(this.ParentNetworkView);
Vector offset = curMousePoint - lastMousePoint;
if (offset.X != 0.0 &&
offset.Y != 0.0)
{
lastMousePoint = curMousePoint;
RaiseEvent(new ExecutionConnectorItemDraggingEventArgs(ExecutionConnectorDraggingEvent, this, offset.X, offset.Y));
}
e.Handled = true;
}
else if (isLeftMouseDown)
{
if (this.ParentNetworkView != null &&
this.ParentNetworkView.EnableConnectionDragging)
{
//
// The user is left-dragging the connector and connection dragging is enabled,
// but don't initiate the drag operation until
// the mouse cursor has moved more than the threshold distance.
//
Point curMousePoint = e.GetPosition(this.ParentNetworkView);
var dragDelta = curMousePoint - lastMousePoint;
double dragDistance = Math.Abs(dragDelta.Length);
if (dragDistance > DragThreshold)
{
//
// When the mouse has been dragged more than the threshold value commence dragging the node.
//
//
// Raise an event to notify that that dragging has commenced.
//
var eventArgs = new ExecutionConnectorItemDragStartedEventArgs(ExecutionConnectorDragStartedEvent, this);
RaiseEvent(eventArgs);
if (eventArgs.Cancel)
{
//
// Handler of the event disallowed dragging of the node.
//
isLeftMouseDown = false;
return;
}
isDragging = true;
this.CaptureMouse();
e.Handled = true;
}
}
}
}
