wpf-devexpress-dot-xpf-dot-grid-dot-treelistview-f4da2b60.md
Allows you to validate nodes, check database constraints, and delete nodes from the database before a user deletes a node from the Data Grid.
Namespace : DevExpress.Xpf.Grid
Assembly : DevExpress.Xpf.Grid.v25.2.dll
NuGet Package : DevExpress.Wpf.Grid.Core
public event EventHandler<TreeListValidateNodeDeletionEventArgs> ValidateNodeDeletion
Public Event ValidateNodeDeletion As EventHandler(Of TreeListValidateNodeDeletionEventArgs)
The ValidateNodeDeletion event's data class is TreeListValidateNodeDeletionEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| DisplayErrorMode | Gets or sets whether to display an error message. Inherited from GridValidateRowDeletionEventArgs. |
| Handled | Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs. |
| Nodes | Gets nodes a user wants to delete. |
| OriginalSource | Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs. |
| Result | Gets or sets information about the error (its type and description). Inherited from GridValidateRowDeletionEventArgs. |
| ResultAsync | Gets or sets a task that asynchronously deletes rows from the underlying data source (database). Inherited from GridValidateRowDeletionEventArgs. |
| RoutedEvent | Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs. |
| RowHandles | Gets handles of rows that a user wants to delete. Inherited from GridValidateRowDeletionEventArgs. |
| Rows | Gets rows that a user wants to delete. Inherited from GridValidateRowDeletionEventArgs. |
| Source | Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs. |
The event data class exposes the following methods:
| Method | Description |
|---|---|
| InvokeEventHandler(Delegate, Object) | When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs. |
| OnSetSource(Object) | When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs. |
You can implement CRUD operations (create, read update, delete). These operations allow users to manage data in the Data Grid. Refer to the following topic for more information: Implement CRUD Operations in a Data-Bound Grid.
View Example: How to Implement CRUD Operations in a Data-Bound Grid
See Also