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ListView.SelectedIndexChanged Event

  • Reference

Definition

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

Occurs when an item's Select button is clicked, after the ListView control handles the select operation.

C# 
public event EventHandler SelectedIndexChanged;

Event Type

EventHandler

Examples

The following example shows how create an event handler for the SelectedIndexChanged event.

ASP.NET (C#) 
<%@ Page language="C#" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    
<script runat="server">
    
  //<Snippet3>
  void ContactsListView_SelectedIndexChanged(Object sender, EventArgs e)
  {
    if (ContactsListView.SelectedIndex >= 0)
      ViewState["SelectedKey"] = ContactsListView.SelectedValue;
    else
      ViewState["SelectedKey"] = null;
  }
  
  void ContactsListView_DataBound(Object sender, EventArgs e)
  {
    for (int i = 0; i < ContactsListView.Items.Count; i++)
    {
      // Ignore values that cannot be cast as integer.
      try
      {
          if ((int)ContactsListView.DataKeys[i].Value == (int)ViewState["SelectedKey"])
              ContactsListView.SelectedIndex = i;
      }
      catch { }
    }
  }
  //</Snippet3>

  void ContactsListView_PagePropertiesChanged(Object sender, EventArgs e)
  {
    ContactsListView.SelectedIndex = -1;
  }

  void ContactsListView_Sorting(Object sender, ListViewSortEventArgs e)
  {
    ContactsListView.SelectedIndex = -1;
  }

  void ClearButton_Click(Object sender, EventArgs e)
  {
    ViewState["SelectedKey"] = null;
    ContactsListView.SelectedIndex = -1;
  }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView SelectedIndex Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView SelectedIndex Example</h3>

      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnDataBound="ContactsListView_DataBound"
        OnSelectedIndexChanged="ContactsListView_SelectedIndexChanged"  
        OnPagePropertiesChanged="ContactsListView_PagePropertiesChanged"
        OnSorting="ContactsListView_Sorting"
        runat="server">
        <LayoutTemplate>
          <asp:Button runat="server" ID="SortButton" 
            CommandArgument="LastName" CommandName="Sort" Text="Sort" />
          <asp:Button runat="server" ID="ClearButton" 
            OnClick="ClearButton_Click" Text="Clear Selection" /><br />
          <table cellpadding="2" border="1" runat="server" id="tblContacts" width="640px">
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="20">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|&lt;&lt; " LastPageText=" &gt;&gt;|"
                NextPageText=" &gt; " PreviousPageText=" &lt; " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
            <td>
              <asp:LinkButton ID="SelectButton" runat="server" CommandName="Select" Text="Select" />
            </td>
          </tr>
        </ItemTemplate>
        <SelectedItemTemplate>
          <tr runat="server" style="background-color:#B0C4DE">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
            <td>&nbsp;</td>
          </tr>
        </SelectedItemTemplate>
      </asp:ListView>

      <!-- This example uses Microsoft SQL Server and connects      -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET    -->
      <!-- expression to retrieve the connection string value       -->
      <!-- from the Web.config file.                                -->
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] 
          FROM Person.Contact">
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

Remarks

The SelectedIndexChanged event is raised when an item's Select button is clicked, after the ListView control handles the select operation. (A Select button is a button control whose CommandName property is set to "Select".) This enables you to perform a custom routine whenever this event occurs, such as updating a status label with information about the currently selected item.

For more information about how to handle events, see Handling and Raising Events.

Applies to

Proizvod Verzije
.NET Framework 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