TreeListView.ValidateNode Event

Occurs when you make changes within a node and move focus to another node.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v21.1.dll

Declaration

public event TreeListNodeValidationEventHandler ValidateNode

Event Data

The ValidateNode event's data class is TreeListNodeValidationEventArgs. The following properties provide information specific to this event:

Property Description
CancellationToken Gets an object that notifies that the Update operation should be canceled. Inherited from GridRowValidationEventArgs.
Culture Gets the culture related to the validation. Inherited from ValidationEventArgs.
ErrorContent Gets or sets an object that describes the validation error. Inherited from ValidationEventArgs.
ErrorType Gets or sets the error icon type. Inherited from ValidationEventArgs.
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.
IsValid Gets or sets a value specifying whether the value is valid. Inherited from ValidationEventArgs.
Node Gets the processed node.
OriginalSource Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Row Gets the processed row. Inherited from GridRowValidationEventArgs.
RowHandle Gets the processed row’s handle. Inherited from GridRowValidationEventArgs.
Source Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
UpdateRowResult Gets or sets a task that allows you to asynchronously post changes to an underlying data source (database). Inherited from GridRowValidationEventArgs.
UpdateSource Gets the action that caused the validation. Inherited from ValidationEventArgs.
UseCancellationToken Gets or sets whether the Update operation can be canceled. Inherited from GridRowValidationEventArgs.
Value Gets the editor’s value. Inherited from ValidationEventArgs.

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.
SetError(Object) Marks the processed input value as invalid and displays an error within the editor. Inherited from ValidationEventArgs.
SetError(Object, ErrorType) Marks the processed input value as invalid and displays an error within the editor with the specified error icon type. Inherited from ValidationEventArgs.

Remarks

Handle this event to validate changes made within the focused node. You can also invoke the CommitEditing method to validate changes.

The Node property returns the processed node.

You can obtain cell values and verify if they meet your validation criteria. If these values are incorrect, set the IsValid property to false.

Refer to the following topic for more information: Row Validation.

If you want to maintain a clean MVVM pattern and process the node validate operation in a View Model, create a command and bind it to the ValidateNodeCommand property.

Use the UpdateRowResult property to validate rows data asynchronously.

See Also