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ASPxGridView.RowValidating Event

Enables you to specify whether row data is valid and whether the row can be updated.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v22.1.dll

NuGet Package: DevExpress.Web

Declaration

public event ASPxDataValidationEventHandler RowValidating

Event Data

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

Property Description
EditorPropertiesErrors Gets a collection of editor errors.
Errors Gets a collection of row errors.
HasErrors Gets whether the processed data item (row, card or record) has errors. Inherited from ASPxGridDataValidationEventArgs.
IsNewRow Gets whether the processed row is new.
Keys Gets a dictionary of field name/value pairs that represent the primary key of the data item (row, card or record) to validate. Inherited from ASPxGridDataValidationEventArgs.
NewValues Gets a dictionary that contains the values of the non-key field name/value pairs in the data item (row, card or record) to be validated. Inherited from ASPxGridDataValidationEventArgs.
OldValues Gets a dictionary that contains the original field name/value pairs in the data item (row, card or record) to validate. Inherited from ASPxGridDataValidationEventArgs.
RowError Gets or sets the error text displayed within the Error Row.
VisibleIndex Gets a visible index of the currently processed data item (row, card or record). Inherited from ASPxGridDataValidationEventArgs.

Remarks

The RowValidating event is automatically raised when a row is about to be updated, and allows you to specify whether its data is valid. To manually validate the edited row, call the ASPxGridView.DoRowValidation method.

To obtain the edited row’s values, use the event parameter’s ASPxGridDataValidationEventArgs.NewValues property. The old values are returned by the ASPxGridDataValidationEventArgs.OldValues property. If the value is invalid, use the ASPxDataValidationEventArgs.Errors property to specify the error description text. As a result, an error icon will be displayed next to the invalid value. Pointing to the icon shows the hint with the error description.

RowValidating

Use the ASPxDataValidationEventArgs.RowError property to specify the error text displayed within the Error Row. This row is automatically displayed below the Edit Form if the RowError property is set to a not empty string.

Example

This example demonstrates how to check the validity of data entered by end-users into a row. Validation is implemented within the ASPxGridView.RowValidating event handler. In this sample, validation fails in the cases listed below:

  • field value(s) is empty;
  • Contact Name and/or Company Name fields are set to a single character.

The ASPxGridView.HtmlRowPrepared event is handled to paint the row’s contents red if the row is invalid. This event is raised for each data row when the corresponding row within the table has been created. This indicates rows within invalid data.

The ASPxGridView.StartRowEditing event is handled to display errors (if any) within the edited row when an end-user switches to an edit mode.

using DevExpress.Web.ASPxGridView;
using System.Collections.Generic;

protected void grid_RowValidating(object sender, 
DevExpress.Web.Data.ASPxDataValidationEventArgs e) {
    // Checks for null values.
    foreach (GridViewColumn column in grid.Columns) {
        GridViewDataColumn dataColumn = column as GridViewDataColumn;
        if (dataColumn == null) continue;
        if (e.NewValues[dataColumn.FieldName] == null)
            e.Errors[dataColumn] = "Value cannot be null.";
    }
    // Displays the error row if there is at least one error.
    if (e.Errors.Count > 0) e.RowError = "Please, fill all fields.";

    if (e.NewValues["ContactName"] != null && 
        e.NewValues["ContactName"].ToString().Length < 2) {
        AddError(e.Errors, grid.Columns["ContactName"], 
        "Contact Name must be at least two characters long.");
    }
    if (e.NewValues["CompanyName"] != null && 
    e.NewValues["CompanyName"].ToString().Length < 2) {
        AddError(e.Errors, grid.Columns["CompanyName"], 
        "Company Name must be at least two characters long.");
    }
    if (string.IsNullOrEmpty(e.RowError) && e.Errors.Count > 0) 
    e.RowError = "Please, correct all errors.";
}

void AddError(Dictionary<GridViewColumn, string> errors, 
GridViewColumn column, string errorText) {
     if(errors.ContainsKey(column)) return;
     errors[column] = errorText;
 }

protected void grid_HtmlRowPrepared(object sender, 
ASPxGridViewTableRowEventArgs e) {
    // Checks whether the generated row has the errors.
    bool hasError = e.GetValue("ContactName").ToString().Length <= 1;
    hasError = hasError || e.GetValue("CompanyName").ToString().Length <= 1;
    hasError = hasError || e.GetValue("Country") == null;
    // If the row has the error(s), its text color is set to red.
    if (hasError)
        e.Row.ForeColor = System.Drawing.Color.Red;
}

protected void grid_StartRowEditing(object sender, 
DevExpress.Web.Data.ASPxStartRowEditingEventArgs e) {
    // Validates the edited row if it isn't a new row,.
    if (!grid.IsNewRowEditing)
        grid.DoRowValidation();
}
See Also