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TdxTreeViewNodeAllowEvent Type

The action permission procedural type for tree nodes.

#Declaration

Delphi
TdxTreeViewNodeAllowEvent = procedure(Sender: TdxCustomTreeView; ANode: TdxTreeViewNode; var Allow: Boolean) of object;

#Parameters

Name Type Description
Sender TdxCustomTreeView

The Tree View control that raised an action permission event.

ANode TdxTreeViewNode

The target tree node.

Allow Boolean

Assign False to this parameter to prohibit users from performing the action. To allow the action, assign False to the parameter.

#Remarks

The OnCollapsing event handler below prohibits the control from collapsing nodes at the top nesting level:

procedure TForm1.dxTreeViewControl1Collapsing(Sender: TdxCustomTreeView;
  ANode: TdxTreeViewNode; var Allow: Boolean);
begin
  if ANode.Parent = Sender.Root then
    Allow := False;
end;

The following Tree View events reference the TdxTreeViewNodeAllowEvent type:

See Also