Did you know that you can get and set events with the TMethod record? Let’s assume you would like to hook an OnClose event of a form:
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type TMyHookObject = class strict private FOldOnClose: TMethod; procedure OnClose(ASender: TObject; var AAction: TCloseAction); ... procedure TMyHookObject.Init(AForm: TForm); begin //Save the old event FOldOnClose := TMethod(AForm.OnClose); //Set the new one AForm.OnClose := OnClose; end; procedure TMyHookObject.OnClose(ASender: TObject; var AAction: TCloseAction); begin //Call the old event if Assigned(FOldOnClose.Data) and Assigned(FOldOnClose.Code) then TCloseEvent(FOldOnClose)(ASender, AAction); //Run your own code ... |
As you can see in the example you can easily store and call events with the help of TMethod.
