GridView.RowUpdating Event

 

Occurs when a row's Update button is clicked, but before the GridView control updates the row.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

Public Event RowUpdating As GridViewUpdateEventHandler

The RowUpdating event is raised when a row's Update button is clicked, but before the GridView control updates the row. This enables you to provide an event-handling method that performs a custom routine, such as canceling the update operation, whenever this event occurs.

A GridViewUpdateEventArgs object is passed to the event-handling method, which enables you to determine the index of the current row and to indicate that the update operation should be canceled. To cancel the update operation, set the Cancel property of the GridViewUpdateEventArgs object to true. You can also manipulate the Keys, OldValues, and NewValues collections, if necessary, before the values are passed to the data source. A common way to use these collections is to HTML-encode the values supplied by the user before they are stored in the data source. This helps to prevent script injection attacks.

System_CAPS_noteNote

The Keys, OldValues and NewValues collections are automatically populated only when the GridView control is bound to data by using the DataSourceID property.

For more information about handling events, see NIB: Consuming Events.

The following example demonstrates how to use the RowUpdating event to update the values in the data source object when the data source is set programmatically.

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  Protected Sub Page_Load()

    If Not Page.IsPostBack Then
      ' Create a new table.
      Dim taskTable As New DataTable("TaskList")

      ' Create the columns.
      taskTable.Columns.Add("Id", GetType(Integer))
      taskTable.Columns.Add("Description", GetType(String))
      taskTable.Columns.Add("IsComplete", GetType(Boolean))

      'Add data to the new table.
      For i = 0 To 19
        Dim tableRow = taskTable.NewRow()
        tableRow("Id") = i
        tableRow("Description") = "Task " + i.ToString()
        tableRow("IsComplete") = False
        taskTable.Rows.Add(tableRow)
      Next

      'Persist the table in the Session object.
      Session("TaskTable") = taskTable

      'Bind data to the GridView control.
      BindData()
    End If

  End Sub

  Protected Sub TaskGridView_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)
    TaskGridView.PageIndex = e.NewPageIndex
    'Bind data to the GridView control.
    BindData()
  End Sub

  Protected Sub TaskGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
    'Set the edit index.
    TaskGridView.EditIndex = e.NewEditIndex
    'Bind data to the GridView control.
    BindData()
  End Sub

  Protected Sub TaskGridView_RowCancelingEdit()
    'Reset the edit index.
    TaskGridView.EditIndex = -1
    'Bind data to the GridView control.
    BindData()
  End Sub

  Protected Sub TaskGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
    'Retrieve the table from the session object.
    Dim dt = CType(Session("TaskTable"), DataTable)

    'Update the values.
    Dim row = TaskGridView.Rows(e.RowIndex)
    dt.Rows(row.DataItemIndex)("Id") = (CType((row.Cells(1).Controls(0)), TextBox)).Text
    dt.Rows(row.DataItemIndex)("Description") = (CType((row.Cells(2).Controls(0)), TextBox)).Text
    dt.Rows(row.DataItemIndex)("IsComplete") = (CType((row.Cells(3).Controls(0)), CheckBox)).Checked

    'Reset the edit index.
    TaskGridView.EditIndex = -1

    'Bind data to the GridView control.
    BindData()
  End Sub

  Private Sub BindData()
    TaskGridView.DataSource = Session("TaskTable")
    TaskGridView.DataBind()
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>GridView example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

      <asp:GridView ID="TaskGridView" runat="server" 
        AutoGenerateEditButton="True" 
        AllowPaging="true"
        OnRowEditing="TaskGridView_RowEditing"         
        OnRowCancelingEdit="TaskGridView_RowCancelingEdit" 
        OnRowUpdating="TaskGridView_RowUpdating"
        OnPageIndexChanging="TaskGridView_PageIndexChanging">
      </asp:GridView>

    </div>
    </form>
</body>
</html>

.NET Framework
Available since 2.0
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