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TApplication = class(TComponent)


class PASCALIMPLEMENTATION TApplication : public System::Classes::TComponent


Type Visibility Source Unit Parent
class public
Vcl.Forms Vcl.Forms


TApplication is the type used for a GUI windowed application.

TApplication encapsulates a windowed application. The methods and properties introduced in TApplication reflect the fundamentals established in the Windows operating system to create, run, sustain, and destroy an application. TApplication thereby simplifies the interface between the developer and the Windows environment. For this purpose, TApplication encapsulates behavior for:

  • Windows message processing
  • Context-sensitive online help
  • Menu accelerator and key processing
  • Exception handling
  • Managing the fundamental parts defined by the Windows operating system for an application, such as MainWindow, WindowClass, and so on

Each GUI application automatically declares an Application variable as the instance of the application. If the application is not a Web server application, control panel applet, or NT service application, this variable is of type TApplication.

TApplication does not appear on the Component palette, nor is it available in the form designer to visually manipulate; so it has no published properties. Nevertheless, some of its public properties can be set or modified at design time in the Forms and Application pages of the Project|Options dialog box. In addition, you can add a TApplicationEvents component to any form in the project to intercept the application's events, and supply event handlers using the IDE.

Note: For application-wide properties and methods that affect the display, see TScreen.

See Also