Home > Foresight Analytics Platform > Web Application and Desktop Application > Application Development and Functionality Enhancement > Developing Web Application Using DHTML Components > Working with Trees > Classes > TreeList > TreeList.BeforeExpand
BeforeExpand: function(sender, args);
sender. Event source.
args. Event information.
The BeforeExpand event is fired before expanding a tree node.
To execute the example, create a TreeList component named treeListSett. Add a handler for the BeforeExpand event:
treeListSett.BeforeExpand.add(function (sender, args)
{
treeListSett.selectAll();
});
After executing the example clicking the 
icon (before expanding the node) selects all tree nodes.
See also:
