ListView.SelectedIndexChanged Evento

Definição

Ocorre quando o botão de seleção de um item é clicado, após o controle ListView manipular a operação de seleção.Occurs when an item's Select button is clicked, after the ListView control handles the select operation.

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

Tipo de evento

EventHandler

Exemplos

O exemplo a seguir mostra como criar um manipulador de eventos para o SelectedIndexChanged evento.The following example shows how create an event handler for the SelectedIndexChanged event.

<%@ 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>
<%@ Page language="VB" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    
<script runat="server">
    
  '<Snippet3>
  Sub ContactsListView_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    If ContactsListView.SelectedIndex >= 0 Then
      ViewState("SelectedKey") = ContactsListView.SelectedValue
    Else
      ViewState("SelectedKey") = Nothing
    End If
  End Sub

  Sub ContactsListView_DataBound(ByVal sender As Object, ByVal e As EventArgs)
    For i As Integer = 0 To ContactsListView.Items.Count - 1
      ' Ignore values that cannot be cast as integer.
      Try
        If Convert.ToInt32(ContactsListView.DataKeys(i).Value) = Convert.ToInt32(ViewState("SelectedKey")) Then _
          ContactsListView.SelectedIndex = i
      Catch
      End Try
    Next
  End Sub
  '</Snippet3>

  Sub ContactsListView_PagePropertiesChanged(ByVal sender As Object, ByVal e As EventArgs)
    ContactsListView.SelectedIndex = -1
  End Sub

  Sub ContactsListView_Sorting(ByVal sender As Object, ByVal e As ListViewSortEventArgs)
    ContactsListView.SelectedIndex = -1
  End Sub

  Sub ClearButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    ViewState("SelectedKey") = Nothing
    ContactsListView.SelectedIndex = -1
  End Sub
    
</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>

Comentários

O SelectedIndexChanged evento é gerado quando o botão Selecionar de um item é clicado, depois que o ListView controle manipula a operação de seleção.The SelectedIndexChanged event is raised when an item's Select button is clicked, after the ListView control handles the select operation. (Um botão de seleção é um controle de botão cuja CommandName propriedade está definida como "selecionar".) Isso permite que você execute uma rotina personalizada sempre que esse evento ocorrer, como atualizar um rótulo de status com informações sobre o item selecionado no momento.(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.

Para obter mais informações sobre como lidar com eventos, consulte manipulando e gerando eventos.For more information about how to handle events, see Handling and Raising Events.

Aplica-se a

Confira também