The System.Actions unit in Delphi provides classes for creating and managing action lists and action objects. Action objects are components that represent a specific action that can be performed, such as opening a file or printing a document. Action lists are containers for action objects, and they provide a way to group related actions and manage them as a single entity.
Here is an example of how you can use the TActionList and TAction classes from the System.Actions unit to create and manage action objects:
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uses System.Actions, Vcl.ActnList; var ActionList: TActionList; OpenAction: TAction; SaveAction: TAction; PrintAction: TAction; begin ActionList := TActionList.Create(nil); try OpenAction := TAction.Create(ActionList); OpenAction.Caption = ‘Open’; OpenAction.OnExecute = OpenFile; SaveAction := TAction.Create(ActionList); SaveAction.Caption = ‘Save’; SaveAction.OnExecute = SaveFile; PrintAction := TAction.Create(ActionList); PrintAction.Caption = ‘Print’; PrintAction.OnExecute = PrintFile; finally ActionList.Free; end; end; procedure OpenFile(Sender TObject); begin //TODO Implement code to open a file. end; procedure SaveFile(Sender TObject); begin //TODO Implement code to save a file. end; procedure PrintFile(Sender TObject); begin //TODO Implement code to print a file. end; |
In this example, we are creating an action list and three action objects for opening, saving, and printing a file.
To create an action object, we use the TAction class and specify the action list as the parent component. We then set the Caption property to specify the caption for the action object, and we assign event handlers to the OnExecute event to specify the code that should be executed when the action is performed.
To execute an action, we can call the Execute method of the action object. This will trigger the OnExecute event and execute the code specified in the event handler.
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