GridViewUpdateEventHandler Delegate
Assembly: System.Web (in system.web.dll)
'Declaration Public Delegate Sub GridViewUpdateEventHandler ( _ sender As Object, _ e As GridViewUpdateEventArgs _ ) 'Usage Dim instance As New GridViewUpdateEventHandler(AddressOf HandlerMethod)
/** @delegate */ public delegate void GridViewUpdateEventHandler ( Object sender, GridViewUpdateEventArgs e )
JScript supports the use of delegates, but not the declaration of new ones.
Parameters
- sender
The source of the event.
- e
A GridViewUpdateEventArgs object that contains the event data.
The RowUpdating event is raised when a row's Update button is clicked, but before the GridView control updates the row. This allows you to provide an event-handling method that performs a custom routine, such as canceling the update operation, whenever this event occurs.
When you create a GridViewUpdateEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.
The following example demonstrates how to programmatically add a GridViewUpdateEventHandler delegate to the RowUpdating event of a GridView control.
<%@ Page language="VB" %> <script runat="server"> Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) ' Create a new GridView object. Dim authorGridView As GridView = New GridView ' Set the GridView object's properties. authorGridView.ID = "AuthorGridView" authorGridView.DataSourceID = "AuthorsSqlDataSource" authorGridView.AutoGenerateColumns = True authorGridView.AutoGenerateEditButton = True authorGridView.DataKeyNames = New [String]() {"au_id"} ' Programmatically register the event-handling method. AddHandler authorGridView.RowUpdating, AddressOf AuthorsGridView_RowUpdating ' Add the GridView object to the Controls collection ' of the PlaceHolder control. GridViewPlaceHolder.Controls.Add(authorGridView) End Sub Sub AuthorsGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs) ' HTML-encode all user-provided values before updating ' the data source. Dim i As Integer For i = 0 To e.NewValues.Count - 1 Dim entry As DictionaryEntry = e.NewValues(i) e.NewValues(entry.Key) = Server.HtmlEncode(entry.Value.ToString()) Next i End Sub </script> <html> <body> <form runat="server"> <h3>GridViewUpdateEventHandler Example</h3> <asp:label id="Message" forecolor="Red" runat="server"/> <br/> <asp:placeholder id="GridViewPlaceHolder" runat="Server"/> <!-- This example uses Microsoft SQL Server and connects --> <!-- to the Pubs sample database. --> <asp:sqldatasource id="AuthorsSqlDataSource" selectcommand="SELECT [au_id], [au_lname], [au_fname], [address], [city], [state], [zip] FROM [authors]" updatecommand="UPDATE authors SET au_lname=@au_lname, au_fname=@au_fname, address=@address, city=@city, state=@state, zip=@zip WHERE (authors.au_id = @au_id)" connectionstring="server=localhost;database=pubs;integrated security=SSPI" runat="server"> </asp:sqldatasource> </form> </body> </html>
The following example demonstrates how to declaratively add a GridViewUpdateEventHandler delegate to the RowUpdating event of a GridView control.
<%@ Page language="VB" %> <script runat="server"> Sub CustomersGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs) ' Use the CopyTo method to copy the DictionaryEntry objects in the ' NewValues collection to an array. Dim records(e.NewValues.Count - 1) As DictionaryEntry e.NewValues.CopyTo(records, 0) ' Iterate through the array and HTML encode all user-provided values ' before updating the data source. Dim entry As DictionaryEntry For Each entry In records e.NewValues(entry.Key) = Server.HtmlEncode(entry.Value.ToString()) Next End Sub </script> <html> <body> <form runat="server"> <h3>GridView RowUpdating Example</h3> <!-- The GridView control automatically sets the columns --> <!-- specified in the datakeynames property as read-only. --> <!-- No input controls are rendered for these columns in --> <!-- edit mode. --> <asp:gridview id="CustomersGridView" datasourceid="CustomersSqlDataSource" autogeneratecolumns="true" autogenerateeditbutton="true" allowpaging="true" datakeynames="CustomerID" onrowupdating="CustomersGridView_RowUpdating" runat="server"> </asp:gridview> <!-- 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="CustomersSqlDataSource" selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]" updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)" connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" runat="server"> </asp:sqldatasource> </form> </body> </html>
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.