Page Events

In This Topic

NOV Diagram pages provide a number of events, which can be used to get notified when a specific event occurs in the drawing page.

Shape Inserted and Removed Events

Diagram shapes are added to the Items property of the page. To get notified when a shape has been added or removed from a page, subscribe to the ChildInserted and ChildRemoved events of the page's Items collection as shown below:

Shape Inserted and Removed Events	Copy Code
NPage page = drawingView.ActivePage; page.Items.ChildInserted += OnPageChildInserted; page.Items.ChildRemoved += OnPageChildRemoved; private void OnPageChildInserted(NInsertChildEventArgs arg) { NShape shape = arg.InsertedNode as NShape; if (shape != null) { NMessageBox.Show("Shape Name: " + shape.Name, "Shape Inserted"); } } private void OnPageChildRemoved(NRemoveChildEventArgs arg) { NShape shape = arg.RemovedNode as NShape; if (shape != null) { NMessageBox.Show("Shape Name: " + shape.Name, "Shape Removed"); } }

Shape Inserted and Removed Events

Copy Code

NPage page = drawingView.ActivePage;
page.Items.ChildInserted += OnPageChildInserted;
page.Items.ChildRemoved += OnPageChildRemoved;

private void OnPageChildInserted(NInsertChildEventArgs arg)
{
    NShape shape = arg.InsertedNode as NShape;
    if (shape != null)
    {
        NMessageBox.Show("Shape Name: " + shape.Name, "Shape Inserted");
    }
}
private void OnPageChildRemoved(NRemoveChildEventArgs arg)
{
    NShape shape = arg.RemovedNode as NShape;
    if (shape != null)
    {
        NMessageBox.Show("Shape Name: " + shape.Name, "Shape Removed");
    }
}

User Input Events

The page also provides many user input events, which are raised when the user moves or clicks with the mouse or when he presses keys from the keyboard. The following code example demonstrates how to handle page double-clicks with the left mouse button:

Page Mouse Down Event	Copy Code
page.MouseDown += OnPageMouseDown; private static void OnPageMouseDown(NMouseButtonEventArgs arg) { // Check if this is a double click with the left mouse button if (arg.Button == ENMouseButtons.Left && arg.Clicks == 2) { // Get the double-clicked shape NShape shape = arg.TargetNode as NShape; if (shape == null) { shape = arg.TargetNode.GetFirstAncestor<NShape>(); } if (shape != null) { // Show a message box NMessageBox.Show("Shape double clicked", "Double Click"); } } }

Page Mouse Down Event

Copy Code

page.MouseDown += OnPageMouseDown;

private static void OnPageMouseDown(NMouseButtonEventArgs arg)
{
    // Check if this is a double click with the left mouse button
    if (arg.Button == ENMouseButtons.Left && arg.Clicks == 2)
    {
        // Get the double-clicked shape
        NShape shape = arg.TargetNode as NShape;
        if (shape == null)
        {
            shape = arg.TargetNode.GetFirstAncestor<NShape>();
        }

        if (shape != null)
        {
            // Show a message box
            NMessageBox.Show("Shape double clicked", "Double Click");
        }
    }
}

If you are interested on the MouseDown event of individual shapes, check the Shape Events topic.