One or more of the .NET controls in the Progress Developer Studio for OpenEdge Toolbox can be encapsulated into a reusable unit called the ABL User Control. ABL User Controls are sometimes referred to as composite controls because they are groupings of existing controls. They are useful when you have a specific grouping of controls that is repeated in your application. With an ABL User Control, you can drag and drop the same group on any number of forms in your project.
Like the other forms in the Visual Designer, the ABL User Control is a selection on the File > New menu. After you add controls to the form (and define their properties, data bindings, event logic, etc.), you add the user control to the Toolbox. The user control is then available to be dragged and dropped on other ABL forms in the project.
Note: There is another type of custom control supported by the Visual Designer—the inherited control. Inherited controls are described in Adding HelpButton.cls to the Toolbox.
Leftbar.cls is one of the building blocks of the login dialog. It is an ABL User Control that allows you to choose a user and set the color scheme for the application.
add LeftBar.cls to the project:
1. Expand the openedge node in the SampleApp project.
2. Right-click on the ui node.
3. Choose New > ABL User Control.
4. In the New ABL User Control wizard, type LeftBar in the User Control name field as shown in the following illustration:
Notice that the Inherits field indicates that the control, LeftBar, is an instance of the Progress.Windows.UserControl class.
5. Click Finish.
LeftBar.cls appears with a resizable container displayed in the Visual Designer Canvas as shown in the following illustration:
