thanks, I guess your solution was for a grid.

I found the way, I wanted standard and to show checkbox. it was setting the Override->NodeStyle

Do you know how I can iterate the checkbox and check them? Can I disable the checkbox also?

 If you want CheckBoxes on a node in Standard style, you set the NodeStyle on the Override. But there's no way to disable the checkbox in this case without disabling the whole node. Maybe you can cancel the BeforeCheck event - I'm not sure if it's cancellable. 

 Yeah I  found the CheckState to check uncheck the checkbox. 

 I'm having a hard time to find a way to disable a checkbox but with the node still expandable.

My solution was for a winTree with columns in outlook mode.  In that mode the winTree works a bit like a grid and a bit like a tree.

If you are using standard mode, then I'm guessing you have no columns and you are looking to have a selection checkbox on the node itself?

There is a property called CheckedState on the node.  Never used it, but maybe you can find somethign useful on it in the onlien documentation or just experiment with it a bit...