Represents one or more vertices that might be dragged with the mouse.
Create an instance of this class when a vertex is clicked. When the mouse is moved, check MouseDrag.OnMouseMove to determine whether the mouse has moved far enough to begin a vertex drag. If returns true, call to create a Visual to represent the dragged vertices.

Call CancelDrag if the user wants to cancel the drag operation.

Call RemoveMetadataFromVertices when the drag operation completes or is cancelled.

Inheritance: MouseDragWithVisual
DraggedVertices Class Documentation
Ejemplo n.º 1
0
    OnMouseDownLeft
    (
        MouseButtonEventArgs e,
        Point oMouseLocation,
        IVertex oClickedVertex
    )
    {
        AssertValid();

        if ( m_eMouseMode == MouseMode.Translate ||
            Keyboard.IsKeyDown(Key.Space) )
        {
            // The user might want to translate the zoomed graph by dragging
            // with the mouse.

            StartTranslationDrag(oMouseLocation);
            return;
        }

        if (m_eMouseMode == MouseMode.ZoomIn)
        {
            ZoomViaMouse(e, MouseLeftClickZoomFactor);
            return;
        }

        if (m_eMouseMode == MouseMode.ZoomOut)
        {
            ZoomViaMouse(e, 1.0 / MouseLeftClickZoomFactor);
            return;
        }

        if (oClickedVertex == null)
        {
            // The user clicked on part of the graph not covered by a vertex.

            OnMouseDownLeftVertexNotClicked(oMouseLocation);
            return;
        }

        // If the control key is pressed, clicking a vertex should invert its
        // selected state.  Otherwise...
        //
        // In Select mode, clicking an unselected vertex should clear the
        // selection and then select the vertex.  Clicking a selected vertex
        // should leave the vertex selected.
        //
        // In AddToSelection mode, clicking a vertex should select it.
        //
        // In SubtractFromSelection mode, clicking a vertex should deselect
        // it.

        Boolean bClickedVertexIsSelected = VertexOrEdgeIsSelected(
            oClickedVertex);

        Boolean bSelectClickedVertex = true;

        if ( ControlKeyIsPressed() )
        {
            bSelectClickedVertex = !bClickedVertexIsSelected;
        }
        else if (m_eMouseMode == MouseMode.Select)
        {
            if (!bClickedVertexIsSelected)
            {
                SetAllVerticesSelected(false);
                SetAllEdgesSelected(false);
            }
        }
        else if (m_eMouseMode == MouseMode.SubtractFromSelection)
        {
            bSelectClickedVertex = false;
        }

        SetVertexSelected(oClickedVertex, bSelectClickedVertex,
            m_bMouseAlsoSelectsIncidentEdges);

        // In Select and AddToSelection mode, double-clicking a vertex provides
        // special behavior.

        if (
            Keyboard.Modifiers != 0
            ||
            (m_eMouseMode != MouseMode.Select &&
                m_eMouseMode != MouseMode.AddToSelection)
            )
        {
            m_oDoubleClickedVertexInfo = null;
        }
        else if (e.ClickCount == 2)
        {
            OnVertexDoubleClickLeft(oClickedVertex);
        }
        else if (m_oDoubleClickedVertexInfo != null &&
            m_oDoubleClickedVertexInfo.Vertex != oClickedVertex)
        {
            // (The above "else if" test is required because double-clicking a
            // vertex results in this method being called twice: once with
            // e.ClickCount = 1, and again with e.ClickCount = 2.  We don't
            // want to clear m_oDoubleClickedVertexInfo unnecessarily during
            // this sequence.)

            m_oDoubleClickedVertexInfo = null;
        }

        if (
            m_bAllowVertexDrag
            &&
            (m_eMouseMode == MouseMode.Select ||
                m_eMouseMode == MouseMode.AddToSelection)
            &&
            m_oSelectedVertices.Count > 0
            )
        {
            // The user might want to drag the selected vertices.  Save the
            // mouse location for use within the MouseMove event.

            m_oVerticesBeingDragged = new DraggedVertices(
                m_oSelectedVertices.ToArray(), oMouseLocation,
                this.GraphRectangle, m_oLayout.Margin);

            this.Cursor = Cursors.ScrollAll;
            Mouse.Capture(this);
        }
    }