Avoid deselecting currently selected shape while clicking on the diagram

[Laurent Kempé]

Hi

I would like to avoid deselecting currently selected shape while clicking on the diagram.
When you click on the diagram, out of a shape, the currently selected shape is deselected.
I couldn't find a way to configure or do that.
Thanks for your help.

Cheers
Laurent Kempé

[Petar Mladenov]

Hi Laurent,

 The code below uses the MouseLeftButtonDown event of the RadDiagram, checks whether the clicked element is the RadDiagram and if yes, prevents the selection:

public partial class MainWindow : Window
    {
        private bool shouldPreventSelection = false;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void diagram_PreviewSelectionChanged_1(object sender, SelectionChangedEventArgs e)
        {
            if (this.shouldPreventSelection)
            {
                e.Handled = true;
                this.shouldPreventSelection = false;
            }
        }

        private void diagram_MouseLeftButtonDown_1(object sender, MouseButtonEventArgs e)
        {
            var element = this.diagram.InputHitTest(e.GetPosition(this));
            if( element != null && element.GetType() == typeof(DiagramSurface))
            {
                this.shouldPreventSelection = true;
            }
        }
    }

Let us know if the suggested approach is suitable for you. 

All the best,
Petar Mladenov
the Telerik team

[Petar Mladenov]

Hello Laurent,

 This is ok if we don't use Rectangle Selection. Have you considered using it?  What is the expected behavior that you wish to achieve when using it ?

Greetings,
Petar Mladenov
the Telerik team

[Laurent Kempé]

Hi Petar,

Thanks it works correctly after changing this line

            var element = rootDiagram.InputHitTest(e.GetPosition(rootDiagram));  //replacing the this

I don't know why I didn't found the PreviewSelectionChange and seen only the SelectionChange event. Maybe I was reading too much the doc which mention only Selectionchanged on http://www.telerik.com/help/wpf/raddiagrams-events-diagram.html and should have searched more in the code.

Never the less know it works the way I want, so thank you!

Cheers
Laurent Kempé

[Laurent Kempé]

Hi Petar ,

Yeah I don't use it so it is fine!

Cheers
Laurent Kempé

[Tina Stancheva]

Hi Laurent,

We're happy that the suggested solution works for you. Also, I'd like to thank you for notifying us about the documentation issue - we now added the PreviewSelectionChanged event description in the events article and the change will be reflected with the next upload of the online documentation.

I updated your Telerik points for this feedback.

All the best,
Tina Stancheva
the Telerik team

[Laurent Kempé]

Hi Tina

Thanks