Occurs when a Delete button within a DetailsView control is clicked, but before the delete operation.
Assembly: System.Web (in System.Web.dll)
The event is raised when a Delete button within the DetailsView control is clicked, but before the delete operation. This allows you to provide an event handler that performs a custom routine, such as canceling the delete operation, whenever this event occurs.
A DetailsViewDeleteEventArgs object is passed to the event handler, which allows you to determine the index of the record being deleted and to indicate that the delete operation should be canceled. To cancel the delete operation, set the Cancel property to true. You can also manipulate the Keys and Values collections, if necessary, before the values are passed to the data source.
For more information about handling events, see Consuming Events.
The following code example demonstrates how to use the event to cancel the delete operation if the user attempts to delete the last item from the DetailsView control.
<%@ Page language="VB" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Sub CustomerDetailView_ItemDeleting(ByVal sender As Object, ByVal e As DetailsViewDeleteEventArgs) ' Cancel the delete operation if the user attempts to delete the last ' record from the data source. If (CustomerDetailView.DataItemCount <= 1) Then e.Cancel = True MessageLabel.Text = "You must keep at least one store." Else MessageLabel.Text = "" End If End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>DetailsView ItemDeleting Example</title> </head> <body> <form id="Form1" runat="server"> <h3>DetailsView ItemDeleting Example</h3> <asp:detailsview id="CustomerDetailView" datasourceid="DetailsViewSource" datakeynames="CustomerID" autogeneratedeletebutton="true" autogeneraterows="true" allowpaging="true" onitemdeleting="CustomerDetailView_ItemDeleting" runat="server"> <fieldheaderstyle backcolor="Navy" forecolor="White"/> </asp:detailsview> <asp:Label id="MessageLabel" forecolor="Red" runat="server"/> <!-- This example uses Microsoft SQL Server and connects --> <!-- to the Northwind sample database. Use an ASP.NET --> <!-- expression to retrieve the connection string value --> <!-- from the web.config file. --> <asp:SqlDataSource ID="DetailsViewSource" runat="server" ConnectionString= "<%$ ConnectionStrings:NorthWindConnectionString%>" InsertCommand="INSERT INTO [Customers]([CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country]) VALUES (@CustomerID, @CompanyName, @Address, @City, @PostalCode, @Country)" SelectCommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]" DeleteCommand="DELETE FROM [Customers] WHERE [CustomerID] = @CustomerID" > </asp:SqlDataSource> </form> </body> </html>