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ListView.Sorting Evento

Definizione

Si verifica quando viene richiesta un'operazione di ordinamento, ma prima che il controllo ListView gestisca l'operazione di ordinamento.

public:
 event EventHandler<System::Web::UI::WebControls::ListViewSortEventArgs ^> ^ Sorting;
public event EventHandler<System.Web.UI.WebControls.ListViewSortEventArgs> Sorting;
member this.Sorting : EventHandler<System.Web.UI.WebControls.ListViewSortEventArgs> 
Public Custom Event Sorting As EventHandler(Of ListViewSortEventArgs) 

Tipo evento

Esempio

Nell'esempio seguente viene illustrato come creare un gestore eventi per l'evento Sorting .

<%@ 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">
  //<Snippet2>
  void ContactsListView_Sorting(Object sender, ListViewSortEventArgs e)
  {
    // Check the sort direction to set the image URL accordingly.
    string imgUrl;
    if (e.SortDirection == SortDirection.Ascending)
      imgUrl = "~/images/ascending.gif";
    else
      imgUrl = "~/images/descending.gif";
      
    // Check which field is being sorted
    // to set the visibility of the image controls.
    Image sortImage1 = (Image) ContactsListView.FindControl("SortImage1");
    Image sortImage2 = (Image)ContactsListView.FindControl("SortImage2");
    Image sortImage3 = (Image)ContactsListView.FindControl("SortImage3");
    switch (e.SortExpression)
    {
      case "FirstName":
        sortImage1.Visible = true;
        sortImage1.ImageUrl = imgUrl;
        sortImage2.Visible = false;
        sortImage3.Visible = false;
        break;
      case "LastName":
        sortImage1.Visible = false;
        sortImage2.Visible = true;
        sortImage2.ImageUrl = imgUrl;
        sortImage3.Visible = false;
        break;
      case "EmailAddress":
        sortImage1.Visible = false;
        sortImage2.Visible = false;
        sortImage3.Visible = true;
        sortImage3.ImageUrl = imgUrl;
        break;
    }
  }
  //</Snippet2>
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView Sorting Example</title>
    <style type="text/css">
      body  { font: 10pt Trebuchet MS, Arial, Tahoma; }
      td { border: 1px solid #E6E6FA; }
      .header {	background: #B0C4DE; }
      .alternatingItem { background: #edf5fd; }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView Sorting Example</h3>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        OnSorting="ContactsListView_Sorting"
        runat="server">
        <LayoutTemplate>
          <table width="640px" runat="server" id="tblContacts">
            <tr class="header" align="center" runat="server">
              <td>
                <asp:LinkButton runat="server" ID="SortByFirstNameButton"
                  CommandName="Sort" Text="First Name" 
                  CommandArgument="FirstName"/>
                <asp:Image runat="server" ID="SortImage1" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
              <td>
                <asp:LinkButton runat="server" ID="SortByLastNameButton"
                  CommandName="Sort" Text="Last Name"
                  CommandArgument="LastName" />
                <asp:Image runat="server" ID="SortImage2" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
              <td>
                <asp:LinkButton runat="server" ID="SortByEmailButton"
                  CommandName="Sort" Text="Email Address" 
                  CommandArgument="EmailAddress" />
                <asp:Image runat="server" ID="SortImage3" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <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>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <AlternatingItemTemplate>
          <tr class="alternatingItem" runat="server">
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </AlternatingItemTemplate>
      </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">
 '<Snippet2>
  Sub ContactsListView_Sorting(ByVal sender As Object, ByVal e As ListViewSortEventArgs) 
  
    ' Check the sort direction to set the image URL accordingly.
    Dim imgUrl As String
    If e.SortDirection = SortDirection.Ascending Then
      imgUrl = "~/images/ascending.gif"
    Else
      imgUrl = "~/images/descending.gif"
    End If
    
    ' Check which field is being sorted
    ' to set the visibility of the image controls.
    Dim sortImage1 As Image = CType(ContactsListView.FindControl("SortImage1"), Image)
    Dim sortImage2 As Image = CType(ContactsListView.FindControl("SortImage2"), Image)
    Dim sortImage3 As Image = CType(ContactsListView.FindControl("SortImage3"), Image)
    
    Select Case e.SortExpression
      Case "FirstName"
        sortImage1.Visible = True
        sortImage1.ImageUrl = imgUrl
        sortImage2.Visible = False
        sortImage3.Visible = False
      Case "LastName"
        sortImage1.Visible = False
        sortImage2.Visible = True
        sortImage2.ImageUrl = imgUrl
        sortImage3.Visible = False
      Case "EmailAddress"
        sortImage1.Visible = False
        sortImage2.Visible = False
        sortImage3.Visible = True
        sortImage3.ImageUrl = imgUrl
    End Select
    
  End Sub
  '</Snippet2>
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView Sorting Example</title>
    <style type="text/css">
      body  { font: 10pt Trebuchet MS, Arial, Tahoma; }
      td { border: 1px solid #E6E6FA; }
      .header {	background: #B0C4DE; }
      .alternatingItem { background: #edf5fd; }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView Sorting Example</h3>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        OnSorting="ContactsListView_Sorting"
        runat="server">
        <LayoutTemplate>
          <table width="640px" runat="server" id="tblContacts">
            <tr class="header" align="center" runat="server">
              <td>
                <asp:LinkButton runat="server" ID="SortByFirstNameButton"
                  CommandName="Sort" Text="First Name" 
                  CommandArgument="FirstName"/>
                <asp:Image runat="server" ID="SortImage1" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
              <td>
                <asp:LinkButton runat="server" ID="SortByLastNameButton"
                  CommandName="Sort" Text="Last Name"
                  CommandArgument="LastName" />
                <asp:Image runat="server" ID="SortImage2" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
              <td>
                <asp:LinkButton runat="server" ID="SortByEmailButton"
                  CommandName="Sort" Text="Email Address" 
                  CommandArgument="EmailAddress" />
                <asp:Image runat="server" ID="SortImage3" 
                  ImageUrl="~/images/ascending.gif" Visible="false" />
              </td>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <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>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <AlternatingItemTemplate>
          <tr class="alternatingItem" runat="server">
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("FirstName") %>' />
            </td>
            <td>
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Eval("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </AlternatingItemTemplate>
      </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>

Commenti

L'evento Sorting viene generato quando si fa clic su un pulsante Ordina o viene chiamato il Sort metodo , ma prima che il ListView controllo gestisca l'operazione di ordinamento. Un pulsante Ordina è un controllo pulsante la cui CommandName proprietà è impostata su "Ordina". In questo modo è possibile eseguire una routine personalizzata ogni volta che si verifica questo evento, ad esempio la personalizzazione dell'espressione di ordinamento.

Un ListViewSortEventArgs oggetto viene passato al gestore eventi, che consente di determinare l'espressione di ordinamento per la colonna. Consente inoltre di indicare che l'operazione di ordinamento deve essere annullata. Per annullare l'operazione di ordinamento, impostare la Cancel proprietà dell'oggetto ListViewSortEventArgs su true.

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

Si applica a

Vedi anche