Infralution Support

[Mark Johnson]

Is there an event to find out the user collapsed a node in the tree?

The scenario is I need to change selection to the node that is collapsed if the currently selected row is under that node in the tree.

Thanks,

Mark

[Infralution]

There is currently no event to notify you of this (since generally VirtualTree handles obtaining data on demand - which this what the expand/collapse events of other trees are typically used for).

You can however achieve what you want by using the widget framework to change the behaviour of the "ExpansionWidget" (see the section in the online help on "Custom Painting and Mouse Handling" under "Customizing Appearance" for more information)

To do this you derive a new ExpansionWidget class as follows:

[Mark Johnson]

Thanks for the response.

That's close to what I want.

I specifcally need to only select the collapsed node if the currently selected node is a child of the node being collapsed. So the user has to always have an item selected that is not collapsed. I don't need to do anything on expanding, just collapsing.

Thanks,

Mark

[Infralution]

You could change the OnMouseDown method to only call the RowWidget.OnMouseDown method if the currently selected row (if any) is a child of the row and the row is expanded eg:

public override void OnMouseDown(MouseEventArgs e)
{
if (this.Row.Expanded)
{
Row selectedRow = Tree.SelectedRow;
if (selectedRow != null && selectedRow.ParentRow == this.Row)
{
RowWidget.OnMouseDown(e);
}
}
base.OnMouseDown (e);
}

This assumes you a using single selection mode. If you are using multiple selection you would need to check each row in the SelectedRows.
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Infralution Support

[Mark Johnson]

Thanks for the help.

I end up getting it to work.