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GridView.RowUpdating Event

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

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

C# 
public event System.Web.UI.WebControls.GridViewUpdateEventHandler RowUpdating;

Event Type

GridViewUpdateEventHandler

Examples

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.

ASP.NET (C#) 
<%@ Page Language="C#" %>
<%@ 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 void Page_Load(object sender, EventArgs e)
  {
          
    if (!Page.IsPostBack)
    {
      // Create a new table.
      DataTable taskTable = new DataTable("TaskList");
      
      // Create the columns.
      taskTable.Columns.Add("Id", typeof(int));
      taskTable.Columns.Add("Description", typeof(string));
      taskTable.Columns.Add("IsComplete", typeof(bool) );

      //Add data to the new table.
      for (int i = 0; i < 20; i++)
      {
        DataRow tableRow = taskTable.NewRow();
        tableRow["Id"] = i;
        tableRow["Description"] = "Task " + i.ToString();
        tableRow["IsComplete"] = false;            
        taskTable.Rows.Add(tableRow);
      }

      //Persist the table in the Session object.
      Session["TaskTable"] = taskTable;

      //Bind data to the GridView control.
      BindData();
    }

  }

  protected void TaskGridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
  {
    TaskGridView.PageIndex = e.NewPageIndex;
    //Bind data to the GridView control.
    BindData();
  }

  protected void TaskGridView_RowEditing(object sender, GridViewEditEventArgs e)
  {
    //Set the edit index.
    TaskGridView.EditIndex = e.NewEditIndex;
    //Bind data to the GridView control.
    BindData();
  }

  protected void TaskGridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
  {
    //Reset the edit index.
    TaskGridView.EditIndex = -1;
    //Bind data to the GridView control.
    BindData();
  }

  protected void TaskGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
  {    
    //Retrieve the table from the session object.
    DataTable dt = (DataTable)Session["TaskTable"];

    //Update the values.
    GridViewRow row = TaskGridView.Rows[e.RowIndex];
    dt.Rows[row.DataItemIndex]["Id"] = ((TextBox)(row.Cells[1].Controls[0])).Text;
    dt.Rows[row.DataItemIndex]["Description"] = ((TextBox)(row.Cells[2].Controls[0])).Text;
    dt.Rows[row.DataItemIndex]["IsComplete"] = ((CheckBox)(row.Cells[3].Controls[0])).Checked;

    //Reset the edit index.
    TaskGridView.EditIndex = -1;

    //Bind data to the GridView control.
    BindData();
  }

  private void BindData()
  {
    TaskGridView.DataSource = Session["TaskTable"];
    TaskGridView.DataBind();
  }
</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>

Remarks

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.

Poznámka

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 how to handle events, see Handling and Raising Events.

Applies to

Produkt Verzie
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also