delphivcl.Application is the type used for a GUI windowed application. Application encapsulates a windowed application. The methods and properties introduced in the Application reflect the fundamentals established in the Windows operating system to create, run, sustain, and destroy an application.
Application thereby simplifies the interface between the developer and the Windows environment. For this purpose, the Application 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 Application.
Application does not appear on the Component palette, nor is it available in the form designer to visually manipulate; so it has no published properties.
We can browse all the properties, methods, and built-in properties of the delphivcl.Application in Python using dir() command:
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import delphivcl dir(delphivcl.Application) |
See the responses in command prompt:
See them more clearly here:
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['ActionUpdateDelay', 'ActivateHint', 'Active', 'ActiveFormHandle', 'AddPopupForm', 'AfterConstruction', 'AllowTesting', 'ApplyBiDiKeyboardLayout', 'ApplyNonBiDiKeyboardLayout', 'Assign', 'AutoDragDocking', 'BeforeDestruction', 'BeginInvoke', 'BiDiKeyboard', 'BiDiMode', 'BindMethodsToEvents', 'BringToFront', 'CPP_ABI_1', 'CPP_ABI_2', 'CPP_ABI_3', 'CancelHint', 'ClassInfo', 'ClassName', 'ClassNameIs', 'ClassParent', 'ClassType', 'CleanupInstance', 'ComObject', 'ComponentCount', 'ComponentIndex', 'ComponentState', 'ComponentStyle', 'Components', 'ControlDestroyed', 'Create', 'CreateForm', 'CreateHandle', 'CurrentHelpFile', 'DefaultFont', 'DefaultHandler', 'DesignInfo', 'Destroy', 'DestroyComponents', 'Destroying', 'DialogHandle', 'Dispatch', 'DisposeOf', 'DoApplicationIdle', 'EndFunctionInvoke', 'EndInvoke', 'EnumAllWindowsOnActivateHint', 'Equals', 'ExeName', 'ExecuteAction', 'FieldAddress', 'FindComponent', 'Free', 'FreeInstance', 'FreeNotification', 'FreeOnRelease', 'GetEnumerator', 'GetHashCode', 'GetInterface', 'GetInterfaceEntry', 'GetInterfaceTable', 'GetNamePath', 'GetParentComponent', 'Handle', 'HandleException', 'HandleMessage', 'HasParent', 'HelpCommand', 'HelpContext', 'HelpFile', 'HelpJump', 'HelpKeyword', 'HelpShowTableOfContents', 'HelpSystem', 'HideHint', 'Hint', 'HintColor', 'HintHidePause', 'HintMouseMessage', 'HintPause', 'HintShortCuts', 'HintShortPause', 'HookMainWindow', 'HookSynchronizeWakeup', 'Icon', 'InRemoteSession', 'InheritsFrom', 'InitInstance', 'Initialize', 'InsertComponent', 'InstanceSize', 'IsImplementorOf', 'IsMetropolisUI', 'IsRightToLeft', 'MainForm', 'MainFormHandle', 'MainFormOnTaskBar', 'MessageBox', 'MethodAddress', 'MethodName', 'Minimize', 'ModalFinished', 'ModalLevel', 'ModalPopupMode', 'ModalStarted', 'Name', 'NewInstance', 'NonBiDiKeyboard', 'NormalizeAllTopMosts', 'NormalizeTopMosts', 'Observers', 'OnActionExecute', 'OnActionUpdate', 'OnActivate', 'OnDeactivate', 'OnException', 'OnGetActiveFormHandle', 'OnGetMainFormHandle', 'OnHelp', 'OnHint', 'OnIdle', 'OnMessage', 'OnMinimize', 'OnModalBegin', 'OnModalEnd', 'OnRemoteSessionChanged', 'OnRestore', 'OnSettingChange', 'OnShortCut', 'OnShowHint', 'Owner', 'PopupControlWnd', 'ProcessMessages', 'QualifiedClassName', 'ReferenceInterface', 'RemoveComponent', 'RemoveFreeNotification', 'RemovePopupForm', 'Restore', 'RestoreTopMosts', 'Run', 'SafeCallException', 'SetProps', 'SetSubComponent', 'ShowException', 'ShowHint', 'ShowMainForm', 'SingleBufferingInRemoteSessions', 'Tag', 'Terminate', 'Terminated', 'Title', 'ToList', 'ToString', 'ToTuple', 'UnhookMainWindow', 'UnhookSynchronizeWakeup', 'UnitName', 'UnitScope', 'UpdateAction', 'UpdateFormatSettings', 'UpdateMetricSettings', 'UseMetropolisUI', 'UseRightToLeftAlignment', 'UseRightToLeftReading', 'UseRightToLeftScrollBar', 'VCLComObject', '__bound__', '__dir__', '__owned__'] |
Let’s create a Python main function that can run and close an application window:
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def main(): Application.Initialize() Application.Title = "MyDelphiApp" f = MainForm(Application) f.Show() FreeConsole() Application.Run() Application.Destroy() main() |
Table of Contents
Note for beta release users
In practice, the only difference between DelphiVCL for Python release version and the beta version is only in how you write the DelphiVCL. Here is the example for how you import the library:
- Release version:
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from delphivcl import * |
- Beta version:
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from DelphiVCL import * |
Watch this comprehensive introduction to Python GUI Development with DelphiVCL library video by Jim McKeeth:
Check out DelphiVCL which easily allows you to build GUIs for Windows using Python.
Check out Python4Delphi which easily allows you to build Python GUIs for Windows using Delphi.
References & further readings
[1] Embarcadero DocWiki. (2011).
Vcl.Forms.TApplication. Embarcadero DocWiki. Embarcadero Technologies. docwiki.embarcadero.com/Libraries/Sydney/en/Vcl. Forms.TForm
