Order of Events in Windows Forms
The order in which events are raised in Windows Forms applications is of particular interest to developers concerned with handling each of these events in turn. When a situation calls for meticulous handling of events, such as when you are redrawing parts of the form, an awareness of the precise order in which events are raised at run time is necessary. This topic provides some details on the order of events during several important stages in the lifetime of applications and controls. For specific details about the order of mouse input events, see Mouse Events in Windows Forms. For an overview of events in Windows Forms, see Events Overview (Windows Forms). For details about the makeup of event handlers, see Event Handlers Overview (Windows Forms).
Application Startup and Shutdown Events
The Form and Control classes expose a set of events related to application startup and shutdown. When a Windows Forms application starts, the startup events of the main form are raised in the following order:
When an application closes, the shutdown events of the main form are raised in the following order:
The ApplicationExit event of the Application class is raised after the shutdown events of the main form.
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Visual Basic 2005 includes additional application events, such as Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Startup and Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Shutdown. How to: Handle Application Events (Visual Basic) |
Focus and Validation Events
When you change the focus by using the keyboard (TAB, SHIFT+TAB, and so on), by calling the Select or SelectNextControl methods, or by setting the ActiveControl property to the current form, focus events of the Control class occur in the following order:
When you change the focus by using the mouse or by calling the Focus method, focus events of the Control class occur in the following order:
Enter
GotFocus
LostFocus
Leave
Validating
Validated