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Change the Context Menu Strip when right-click at shape or a drawing view

Applies to: Nevron Diagram for .NET

How to change the Context Menu Strip when right-click at shape or a drawing view?

Sometimes your program logic may require to display a personalized context menu when the user right clicks on a specific shape. To achieve this you should subscribe to the drawing view's MouseDown event and update the value ContextMenu property of the drawing view if the specific shape was clicked or set it to null or another context menu if it was not. The following is a simple example:

[C#]
NBasicShapesFactory factory = new NBasicShapesFactory();
factory.DefaultSize = new NSizeF(100, 100);
 
NShape shape = factory.CreateShape(BasicShapes.Rectangle);
shape.Location = new NPointF(100, 100);
document.ActiveLayer.AddChild(shape);
 
view.MouseDown += OnViewMouseDown;

[VB.NET]
Dim factory As NBasicShapesFactory = New NBasicShapesFactory()
factory.DefaultSize = New NSizeF(100, 100)
 
Dim shape As NShape = factory.CreateShape(BasicShapes.Rectangle)
shape.Location = New NPointF(100, 100)
document.ActiveLayer.AddChild(shape)
 
AddHandler view.MouseDown, AddressOf OnViewMouseDown

Here's the code you need in the event handler:

[C#]
private void OnViewMouseDown(object sender, MouseEventArgs e)
{
      // Make sure the right mouse button was clicked
      if (e.Button != MouseButtons.Right)
            return;
 
      // Hit test the drawing document
      NPointF location = new NPointF(e.Location);
      NNodeList shapes = view.Document.HitTest(location, -1, NFilters.Shape2D, view.ProvideDocumentHitTestContext());
      if (shapes.Count == 0)
      {
            // No shape were found under the mouse cursor, so set the context
            // menu of the view to null and return
            view.ContextMenu = null;
            return;
      }
 
      // Create a context menu
      ContextMenu contextMenu = new ContextMenu(new MenuItem[]{
            new MenuItem("Menu Item 1"),
            new MenuItem("Menu Item 2"),
            new MenuItem("-"),
            new MenuItem("Menu Item 3")
      });
 
      // Set the context menu of the drawing view
      view.ContextMenu = contextMenu;
}

[VB.NET]
Private Sub OnViewMouseDown(ByVal sender As Object, ByVal e As MouseEventArgs)
      ' Make sure the right mouse button was clicked
      If e.Button <> MouseButtons.Right Then
            Return
      End If
 
      ' Hit test the drawing document
      Dim location As NPointF = New NPointF(e.Location)
      Dim shapes As NNodeList = view.Document.HitTest(location, -1, NFilters.Shape2D, view.ProvideDocumentHitTestContext())
      If shapes.Count = 0 Then
            ' No shape were found under the mouse cursor, so set the context
            ' menu of the view to null and return
            view.ContextMenu = Nothing
            Return
      End If
 
      ' Create a context menu
      Dim contextMenu As ContextMenu = New ContextMenu(New MenuItem(){ New MenuItem("Menu Item 1"), New MenuItem("Menu Item 2"), New MenuItem("-"), New MenuItem("Menu Item 3") })
 
      ' Set the context menu of the drawing view
      view.ContextMenu = contextMenu
End Sub

Article ID: 17, Created On: 9/29/2010, Modified: 4/8/2013

Comments (2)

Simen Solvang

I am trying to disable the contectMenu of the drawing completely by replacing the ContextMenu property of the nDrawingView instance with an empty ContextMenu. Reading the text above, I would think this code would do it, but it does not:

void frmMain_Load(object sender, System.EventArgs e)
{
m_View.MouseClick += m_View_MouseClick;
}

void m_View_MouseClick(object sender, MouseEventArgs e)
{
m_View.ContextMenu = new ContextMenu();
}

3/19/2013 at 8:11 AM
    Christo Bahchevanov

    In order to disable the context menu of the drawing view you should set the context menu builder of the diagram command bar manager to null:

    manager.ContextMenuBuilder = null;

    4/8/2013 at 8:13 AM
      Simen Solvang

      I am trying to do this, but not sure how to override the right click event, and where.

      Could you supply some sample code for how to do this?

      3/11/2013 at 12:24 PM