This example describes how to use a tree list control to show hierarchical data in XAF WinForms applications. For this purpose, the example uses the TreeListEditor and CategorizedListEditor supplied with the TreeListEditorsWindowsFormsModule.

The example uses the following techniques:

1. A List View that defines objects of a type that implements the ITreeNode interface. This view is displayed by the TreeListEditor.

   Files to review:

   • The Category class.
   • The Category class' descendants: ProjectGroup, Project, and ProjectArea

   For details, refer to the following help topics: TreeList Editors Module and Display a Tree List using the ITreeNode interface.

2. A List View that defines objects of a type that implements the ICategorizedItem interface. This view is displayed by the CategorizedListEditor.

   Files to review:

   • The Issue class
   • The CategoryWithIssues class that is related to the previous class by a one-to-many relationship.

   For details, refer to the following topic: Categorized List.

3. A List View that defines objects of the HCategory type, supplied with the Business Class Library. This view is displayed by the TreeListEditor. The HCategory class is added to the application's business model using the following API: Ways to Add a Business class.

   For details, refer to the following topic: Display a Tree List using the HCategory class.

Pay attention to the following KB article: Layout - There are circumstances that cause the "Error creating window handle" error to occur when you alter the MasterDeailMode option.

• Category.cs
• Issue.cs

• XAF Blazor - How to Implement a TreeList Editor to Display Hierarchical Data

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