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Evento BaseDataList.SelectedIndexChanged

Si verifica quando in un controllo di elenco dei dati viene selezionato un elemento diverso tra gli invii al server.

Spazio dei nomi: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

public event EventHandler SelectedIndexChanged
/** @event */
public void add_SelectedIndexChanged (EventHandler value)

/** @event */
public void remove_SelectedIndexChanged (EventHandler value)

JScript supporta l'utilizzo di eventi ma non la dichiarazione di nuovi.

L'evento SelectedIndexChanged si verifica quando in un controllo di elenco dei dati viene selezionato un elemento diverso tra gli invii al server.

Per ulteriori informazioni sulla gestione di eventi, vedere Utilizzo degli eventi.

Nell'esempio di codice riportato di seguito viene illustrato come fornire in modo dichiarativo un gestore eventi per l'evento SelectedIndexChanged.


<%@ Page Language="C#" AutoEventWireup="True"%>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<html>

<head>

   <script runat="server">

      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));

         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         // Create a DataView from the DataTable.
         DataView dv = new DataView(dt);
         return dv;

      }
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack) 
         {
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
         }

      }

      void IndexChange_Command(Object sender, EventArgs e)
      {
          
         // Display the details of the selected item.
         DetailsLabel.Text = 
            "Item Number: " + ItemsGrid.SelectedItem.Cells[1].Text + "<br>" +
            "Description: " + ItemsGrid.SelectedItem.Cells[2].Text + "<br>" +
            "Price: $" + ItemsGrid.SelectedItem.Cells[3].Text + "<br>";

      }

   </script>

</head>

<body>

   <form runat="server">

      <h3>Declarative BaseDataList SelectedIndexChanged Example</h3>

      Select an item: 

      <br><br>

      <asp:DataGrid id="ItemsGrid" 
           BorderColor="Black"
           ShowFooter="False" 
           CellPadding=3 
           CellSpacing="0"
           HeaderStyle-BackColor="#aaaadd"
           OnSelectedIndexChanged="IndexChange_Command"
           runat="server">

         <Columns>

            <asp:ButtonColumn Text="Select"
                 CommandName="Select"/>

         </Columns>

      </asp:DataGrid>

      <hr>

      <table border="1" bordercolor="black" cellspacing="0">

         <tr bgcolor="#aaaadd">

            <td>

               Details

            </td>

         </tr>

         <tr>

            <td>

               <asp:Label id="DetailsLabel"
                    runat="server"
                    Text="No item selected."/>

            </td>

         </tr>

      </table>

   </form>

</body>
</html>


Nell'esempio di codice riportato di seguito viene illustrato come fornire a livello di codice un gestore eventi per l'evento SelectedIndexChanged.


<%@ Page Language="C#" AutoEventWireup="True"%>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<html>

<head>

   <script runat="server">

      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));

         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         // Create a DataView from the DataTable.
         DataView dv = new DataView(dt);
         return dv;

      }

      void IndexChange_Command(Object sender, EventArgs e)
      {
          
         // Display the details of the selected item.
         DetailsLabel.Text = "Item Number: " + ItemsGrid.SelectedItem.Cells[1].Text + "<br>" +
                              "Description: " + ItemsGrid.SelectedItem.Cells[2].Text + "<br>" +
                              "Price: $" + ItemsGrid.SelectedItem.Cells[3].Text + "<br>";

      }
 
      void Page_Load(Object sender, EventArgs e) 
      {         
 
         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack) 
         {
 
            // Load sample data.
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
            
         }

         // Register event-handling methods.
         ItemsGrid.SelectedIndexChanged += new EventHandler(this.IndexChange_Command);

      }

   </script>

</head>

<body>

   <form runat="server">

      <h3>Programmatic BaseDataList SelectedIndexChanged Example</h3>

      Select an item: 

      <br><br>

      <asp:DataGrid id="ItemsGrid" 
           BorderColor="Black"
           ShowFooter="False" 
           CellPadding=3 
           CellSpacing="0"
           HeaderStyle-BackColor="#aaaadd"
           runat="server">

         <Columns>

            <asp:ButtonColumn Text="Select"
                 CommandName="Select"/>

         </Columns>

      </asp:DataGrid>

      <hr>

      <table border="1" bordercolor="black" cellspacing="0">

         <tr bgcolor="#aaaadd">

            <td>

               Details

            </td>

         </tr>

         <tr>

            <td>

               <asp:Label id="DetailsLabel"
                    runat="server"
                    Text="No item selected."/>

            </td>

         </tr>

      </table>

   </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

.NET Framework non supporta tutte le versioni di ciascuna piattaforma. Per un elenco delle versioni supportate, vedere Requisiti di sistema.

.NET Framework

Supportato in: 2.0 1.1 1.0

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