TreeListColumn.Validate Event

Enables you to validate the active editor's value.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v20.2.dll

Declaration

public event TreeListCellValidationEventHandler Validate
Public Event Validate As TreeListCellValidationEventHandler

Event Data

The Validate event's data class is TreeListCellValidationEventArgs. 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.
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 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

When an end-user modifies the focused cell's value and tries to save the changes (by pressing the ENTER key or moving focus to another cell), the treelist validates a new value. First, this value is validated by the editor itself. Then, the column's Validate event is raised, allowing you to manually validate the cell's value. Note this event is not fired when changing cell values in code.

To learn more, see Cell Validation.

See Also