GridViewUpdateEventArgs.OldValues Property
Gets a dictionary containing the original field name/value pairs in the row to update.
Assembly: System.Web (in System.Web.dll)
Property Value
Type: System.Collections.Specialized.IOrderedDictionaryAn System.Collections.Specialized.IOrderedDictionary object that contains the original values of the field name/value pairs in the row to update.
Use the OldValues property (dictionary) to access the original values of the fields in the row to update. This dictionary contains all fields in the row except the key fields. The key fields are defined in the DataKeyNames property of a GridView control.
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You can access the key fields of the row by using the Keys property. To access the revised values of the non-key fields in the row, use the NewValues property. |
The OldValues property is automatically populated with the original values of all the field name/value pairs in the row. A separate entry is added to the OldValues property for each field in the row.
To determine the field name of an entry, use the DictionaryEntry.Key property of a System.Collections.DictionaryEntry object contained in the OldValues dictionary. To determine the value of an entry, use the DictionaryEntry.Value property.
The following example demonstrates how to use the OldValues property to access the original values of the fields in the row to update. The values are then written to a log file of updated records.
<%@ Page language="VB" %> <%@ import namespace="System.IO" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Sub EmployeesGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs) ' Record the update operation in a log file. ' Create the log text. Dim logText As String = "" ' Append the original field values to the log text. Dim i As Integer For i = 0 To e.OldValues.Count - 1 logText += e.OldValues(i) & ";" Next ' Append the text to a log file. Dim sw As StreamWriter sw = File.AppendText(Server.MapPath(Nothing) & "\updatelog.txt") sw.WriteLine(logText) sw.Flush() sw.Close() End Sub Sub EmployeesGridView_RowUpdated(ByVal sender As Object, ByVal e As GridViewUpdatedEventArgs) If e.Exception Is Nothing Then ' The update operation succeeded. Clear the message label. Message.Text = "" Else ' The update operation failed. Display an error message. Message.Text = e.AffectedRows.ToString() & " rows updated. " & e.Exception.Message e.ExceptionHandled = True End If End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>GridViewUpdateEventArgs OldValues Example</title> </head> <body> <form id="Form1" runat="server"> <h3>GridViewUpdateEventArgs OldValues Example</h3> <asp:label id="Message" forecolor="Red" runat="server"/> <br/> <!-- The GridView control automatically sets the columns --> <!-- specified in the datakeynames attribute as read-only. --> <!-- No input controls are rendered for these columns in --> <!-- edit mode. --> <asp:gridview id="EmployeesGridView" datasourceid="EmployeesSqlDataSource" DataKeyNames="EmployeeID" autogenerateeditbutton="True" onrowupdating="EmployeesGridView_RowUpdating" onrowupdated="EmployeesGridView_RowUpdated" runat="server"> </asp:gridview> <!-- This example uses Microsoft SQL Server and connects --> <!-- to the Northwind sample database. --> <asp:sqldatasource id="EmployeesSqlDataSource" selectcommand="SELECT [EmployeeID], [LastName], [FirstName], [HireDate] FROM [Employees]" updatecommand="UPDATE [Employees] SET [LastName] = @LastName, [FirstName] = @FirstName, [HireDate] = @HireDate WHERE [EmployeeID] = @EmployeeID" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" runat="server" > </asp:sqldatasource> </form> </body> </html>
Available since 2.0
