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TDualList.UpdateAction Method

Updates an action component to reflect the current state of the component.

function UpdateAction(Action: TBasicAction): Boolean; override;

When the application is idle, VCL makes a series of calls to update the properties (such as whether it is enabled, checked, and so on) of every action that is linked to a visible control or menu item. First, VCL generates an OnUpdate event of the action list that contains the action. If the action list does not handle the OnUpdate event, then the action is routed to the Application objectís UpdateAction method, which invokes the OnActionUpdate event handler. If the OnActionUpdate event handler does not update the action, then it is routed to the actionís OnUpdate event handler. If that does not update the action, the active controlís UpdateAction method is called. 

 

The Action parameter specifies the action component that should be updated. UpdateAction returns true if the action component now reflects the state of the component, and false if it did not know how to update the action. If UpdateAction returns false for the active component, VCL calls the active formí 

s UpdateAction method. 

 

Do not call UpdateAction. It is called automatically when the application is idle. As implemented in TComponent, UpdateAction allows the action to update itself with the component as a target. Descendants can override this method to perform updates that reflect class-specific properties or states.

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