ColumnView.ValidateRow Event

Fires when a user edits row cell values and attempts to select another row. Handle this event to check whether these new values are valid, and if not, choose the required behavior (discard edits, show a warning message, ignore errors, or keep the focus on this row until a user enters valid values).

Namespace: DevExpress.XtraGrid.Views.Base

Assembly: DevExpress.XtraGrid.v20.1.dll

Declaration

[DXCategory("Action")]
public event ValidateRowEventHandler ValidateRow
<DXCategory("Action")>
Public Event ValidateRow As ValidateRowEventHandler

Event Data

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

Property Description
ErrorText Gets or sets the error description.
Row Gets the processed row. Inherited from RowObjectEventArgs.
RowHandle Gets the row's handle (position). For the ColumnView.RowUpdated event, this property specifies the previous handle (position) of the currently processed row. Inherited from RowEventArgs.
Valid Gets or sets whether the row validation succeeds.

Remarks

When a user modifies cell values and attempts to move focus to another row, the ValidateRow event fires. Handle this event to review all changes (use the ColumnView.GetRowCellValue and ColumnView.GetRowCellDisplayText method to do that). If any cell value is incorrect, set the e.Valid parameter to false. The following behavior depends on whether you have handled the ColumnView.InvalidRowException event, and if so, what value is assigned to its e.ExceptionMode parameter.

Data Grid - Validation - Row Diagram

If the InvalidRowException event was not handled (or its ExceptionMode equals DisplayError), Data Grid keeps a user on this row and shows a notification message. The ValidateRowEventArgs.ErrorText parameter allows you to modify this message's text. A user can click "No" to dismiss this warning and move to another row, but all edits made to the current row cells will be lost. Note that Data Grid can rollback cell values only when data source entities implement the IEditableObject interface.

ColumnView.ValidateRow_StandardErrorMessage

Instead of validating an entire row, you can handle the BaseView.ValidatingEditor and BaseView.InvalidValueException events to validate every row cell separately.

See the Modify and Validate Cell Values and Internal ErrorInfo Support articles for more information on cell and row validation.

Examples

The example below tracks changes made to the "Units In Stock" and "Units On Order" columns. If an edited record has its "In Stock" value less than "On Order", this row is considered invalid. In this case the e.Valid parameter of the ColumnView.ValidateRow event is set to false.

The default warning message does not pop up since the ExceptionMode parameter of the ColumnView.InvalidRowException event is set to NoAction. Instead, the ColumnView.SetColumnError method displays error icons in both cells.

ColumnView_ValidateRow

using DevExpress.XtraGrid.Views.Base;
using DevExpress.XtraGrid.Columns;
using DevExpress.XtraEditors.Controls;

private void gridView1_ValidateRow(object sender, 
DevExpress.XtraGrid.Views.Base.ValidateRowEventArgs e) {
    GridView view = sender as GridView;
    GridColumn inStockCol = view.Columns["UnitsInStock"];
    GridColumn onOrderCol = view.Columns["UnitsOnOrder"];
    //Get the value of the first column
    Int16 inSt = (Int16)view.GetRowCellValue(e.RowHandle, inStockCol);
    //Get the value of the second column
    Int16 onOrd = (Int16)view.GetRowCellValue(e.RowHandle, onOrderCol);
    //Validity criterion
    if (inSt < onOrd) {
        e.Valid = false;
        //Set errors with specific descriptions for the columns
        view.SetColumnError(inStockCol, "The value must be greater than Units On Order");
        view.SetColumnError(onOrderCol, "The value must be less than Units In Stock");
    }
}

private void gridView1_InvalidRowException(object sender, 
DevExpress.XtraGrid.Views.Base.InvalidRowExceptionEventArgs e) {
    //Suppress displaying the error message box
    e.ExceptionMode = ExceptionMode.NoAction;
}
See Also