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BaseDataList.SelectedIndexChanged Evento

Definizione

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

public:
 event EventHandler ^ SelectedIndexChanged;
public event EventHandler SelectedIndexChanged;
member this.SelectedIndexChanged : EventHandler 
Public Custom Event SelectedIndexChanged As EventHandler 

Tipo evento

Esempio

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


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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title>Declarative BaseDataList SelectedIndexChanged Example</title>
<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 id="form1" 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 style="border-width:1; border-color:Black; margin:0">

         <tr style="background-color:#aaaadd">

            <td>

               Details

            </td>

         </tr>

         <tr>

            <td>

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

            </td>

         </tr>

      </table>

   </form>

</body>
</html>

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title>Declarative BaseDataList SelectedIndexChanged Example</title>
<script runat="server">

      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Integer)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))

         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 8
      
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)
         
         Next i
 
         ' Create a DataView from the DataTable.
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 
 
         ' Load sample data only once when the page is first loaded.
         If Not IsPostBack Then 
         
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
         
         End If

      End Sub

      Sub IndexChange_Command(sender As Object, e As EventArgs)
          
         ' 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 />"

      End Sub

   </script>

</head>

<body>

   <form id="form1" 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" style="border-color:Black; margin:0">

         <tr style="background-color:#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 seguente viene illustrato come fornire un gestore eventi per l'evento SelectedIndexChanged a livello di codice.


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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title>Programmatic BaseDataList SelectedIndexChanged Example</title>
<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 id="form1" 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" style="border-color:Black; margin:0">

         <tr style="background-color:#aaaadd">

            <td>

               Details

            </td>

         </tr>

         <tr>

            <td>

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

            </td>

         </tr>

      </table>

   </form>

</body>
</html>

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title>Programmatic BaseDataList SelectedIndexChanged Example</title>
<script runat="server">

      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Integer)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))

         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 8
      
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)
         
         Next i
 
         ' Create a DataView from the DataTable.
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 
 
         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then 
         
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
         
         End If

         ' Register event-handling methods.
         AddHandler ItemsGrid.SelectedIndexChanged, AddressOf IndexChange_Command
      End Sub

      Sub IndexChange_Command(sender As Object, e As EventArgs)
          
         ' 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 />"

      End Sub

   </script>

</head>

<body>

   <form id="form1" 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"
           DataKeyField="IntegerValue"
           OnSelectedIndexChanged="IndexChange_Command"
           runat="server">

         <Columns>

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

         </Columns>

      </asp:DataGrid>

      <hr />

      <table border="1" style="border-color:Black; margin:0">

         <tr style="background-color:#aaaadd">

            <td>

               Details

            </td>

         </tr>

         <tr>

            <td>

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

            </td>

         </tr>

      </table>

   </form>

</body>
</html>

Commenti

L'evento SelectedIndexChanged viene generato quando viene selezionato un elemento diverso in un controllo elenco di dati tra post al server.

Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.

Si applica a

Vedi anche