A newer version of this page is available. Switch to the current version.

TreeListView.ValidateCell Event

Enables you to specify whether the focused cell's data is valid, and whether the cell's editor can be closed.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v19.2.dll


public event TreeListCellValidationEventHandler ValidateCell
Public Event ValidateCell As TreeListCellValidationEventHandler

Event Data

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

Property Description
Cell Gets the CellValue object consisting of information about the cell being processed. Inherited from GridCellValidationEventArgs.
CellValue Gets the cell's old valid value. Inherited from GridCellValidationEventArgs.
Column Gets the column that contains the processed cell. Inherited from GridCellValidationEventArgs.
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 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.
UpdateSource Gets the action that caused the validation. Inherited from ValidationEventArgs.
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) Displays an error within the editor. Inherited from ValidationEventArgs.
SetError(Object, ErrorType) Displays an error within the editor. Inherited from ValidationEventArgs.


The ValidateCell event occurs before the focused cell's modified value is posted to a data source, allowing to manually validate its new value.

The focused cell's new value is returned by the ValidationEventArgs.Value property. To indicate that the new value is invalid, set the ValidationEventArgs.IsValid property to false.

See Also