Infralution Support

[Raj]

Hi All,

We are trying to create an advanced tree control using Virtual Tree with mulitple checkbox states for each node. To achieve this, we created a custom checkbox control that enhances a standard checkbox control.

When we run this custom control outside Virtual Tree we are able to capture the click and double click events. However, when we attempt to run the same custom control within Virtual Tree, we are unable to capture the click and double click events (and for the matter any other events). Consequently, we can't use the events to trigger critical actions in our custom control.

Specifically we developed

1. A .Net control inherited from Picturebox control which has CheckboxState property and also raises the OnCheckStateChange event when the user clicks and doubleclicks on that control
2. Another Control inherited from Virtual Tree Control which uses the above control as a prefix column

We need to capture the click and double click events (and all other events) of our custom control when we are using that control within the Virtual Tree environment.

Any suggestions that may resolve this issue would be greatly appreciated. Please note that we also submitted this issue to Infralution support and if we are able to resolve this issue we will post the resolution in this forum.

Thanks,

Raj

[Infralution]

We have had a look at the code you forwarded to support and will send you back a modified copy of the solution. This illustrates how to catch events from editor controls. The editor control that is created when you add a an editor in the Virtual Tree designer is a template for the actual controls (there may be many) that are created as needed by Virtual Tree. This means that you can't simply attach an event handler to the template control. Instead Virtual Tree provides a mechanism to allow you to Initialize the editor controls when they are created and this is where you can attach handlers for the controls events.

To do this you add a handler to the CellEditor InitializeControl event. This event is called each time a control is used (the NewControl flag indicates whether the control is being used/created for the first time).