Gtk.TreeSelection.prototype.set_select_function

function set_select_function(func:Gtk.TreeSelectionFunc):void {
    // Gjs wrapper for gtk_tree_selection_set_select_function()
}

Sets the selection function.

If set, this function is called before any node is selected or unselected, giving some control over which nodes are selected. The select function should return true if the state of the node may be toggled, and false if the state of the node should be left unchanged.