Hello Manasi,

The definition of that style for XamDataTreeNodeControl in the XamDataTree.Resources is at a lower scope than the one defined in your Grid.Resources, so yes, this will effectively override the one in your Grid.Resources. This is not to say that you can't have both, though.

I would recommend giving the style in your Grid.Resources an x:Key. This will allow you to base the one in your XamDataTree.Resources off of the one in your Grid.Resources by using BasedOn="{StaticResource gridResourceKey}" in the <Style> tag. Note, though, that this will now remove the style from your secondary XamDataTree, as the style in the Grid.Resources will no longer be implicit. You can reapply this style to your secondary XamDataTree by setting the NodeStyle property of your NodeLayout in the secondary tree to "{StaticResource gridResourceKey}." This will allow you to have both the PreviewMouse event and the context menu on the tree that you need it on.

Please let me know if you have any other questions or concerns on this matter.

Hello Manasi,

I have taken a look at the sample project that you have attached, and the issue here is not so much the PreviewMouseLeftButtonDown event or the NodeCheckedChanged event. The reason your checkboxes are not changing their state is because you are showing a message box on the PreviewMouseLeftButtonDown event. This message box will essentially demand focus, and since the "PreviewMouse" related events actually happen before the actual mouse events, the mouse action never gets triggered, and so the node never gets checked.

After removing these message boxes from your sample, I see that the NodeCheckedChanged event now gets fired, but there is still an issue. Currently, the "SelectedCopy" collection that you are using for your separate tree is getting populated inside of the setter for the bound object array used for the first tree's SelectedDataItems property. This is going to cause issues, because you will be adding more and more nodes to the tree each time this SelectedDataItems array changes. Currently, you are also adding all of the nodes that exist in the SelectedDataItems collection, so you are getting essentially the same behavior as before, but since you are adding them each time this array changes, you will actually end up with many more nodes in your separate tree than you originally had by binding the separate one to the SelectedDataItems array of the original tree.

It appears to me that perhaps you are slightly confused on what I had meant by usage of the PreviewMouseLeftButtonDown and NodeCheckedChanged events from a couple of posts ago. In an attempt to alleviate that possible confusion, I have created a sample project that is based on the one you have sent me. Note, this sample project is very barebones, in that I have removed all of the styling and anything extra that doesn't pertain to the actual selection-based operations between the two trees. This was intentional, as the point of this sample project is to demonstrate what I had tried to describe from a couple of posts to this forum ago, without the inclusion of the extra styling clutter in the code used.

The sample project demonstrating these operations is attached. I hope it helps you.

Please let me know if you have any other questions or concerns on this matter.