ListViewSortEventArgs.SortExpression Свойство

Определение

Пространство имен:: System.Web.UI.WebControls

Сборка:: System.Web.Extensions.dll

Важно!

Некоторые сведения относятся к предварительной версии продукта, в которую до выпуска могут быть внесены существенные изменения. Майкрософт не предоставляет никаких гарантий, явных или подразумеваемых, относительно приведенных здесь сведений.

Возвращает или задает выражение, используемое для сортировки элементов в элементе ListView управления.

public:
 property System::String ^ SortExpression { System::String ^ get(); void set(System::String ^ value); };

public string SortExpression { get; set; }

member this.SortExpression : string with get, set

Public Property SortExpression As String

Значение свойства

String

Выражение, используемое для сортировки элементов в элементе ListView управления.

Примеры

В следующем примере показано, как использовать ListViewSortEventArgs объект для отображения направления сортировки и сортировки столбца. Этот пример кода является частью более крупного примера, предоставленного для ListViewSortEventArgs класса.

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;
  }
}

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

В следующем примере показано, как задать SortExpression свойство для сортировки нескольких столбцов с различными направлениями сортировки, применяемыми к каждому столбцу.

<%@ 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">        

  protected void ContactsListView_Sorting(object sender, ListViewSortEventArgs e)
  {
    // Create the sort expression from the values selected 
    // by the user from the DropDownList controls. Multiple
    // columns can be sorted by creating a sort expression
    // that contains a comma-separated list of field names
    // and optionally directions for each column.
    e.SortExpression = SortList1.SelectedValue + " " +
        DirectionList1.SelectedValue + " ," +
        SortList2.SelectedValue;

    // Determine the sort direction of the second column.
    // The sort direction parameter applies only to the 
    // last column sorted.
    e.SortDirection = SortDirection.Ascending;
    if (DirectionList2.SelectedValue == "DESC")
      e.SortDirection = SortDirection.Descending;

  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server"> 
    <title>SortExpression Example</title>
    <style type="text/css">
      body {  font: 10pt Trebuchet MS; }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
          
      <h3>SortExpression Example</h3>

      <table>
        <tr>
          <td>Sort by:</td>
          <td>
            <asp:DropDownList ID="SortList1" runat="server">
              <asp:ListItem>ContactID</asp:ListItem>
              <asp:ListItem Selected="true">FirstName</asp:ListItem>
              <asp:ListItem>LastName</asp:ListItem>
              <asp:ListItem>EmailAddress</asp:ListItem>              
            </asp:DropDownList>
          </td>
          <td>Sort order:</td>
          <td>
            <asp:DropDownList ID="DirectionList1" runat="server">
              <asp:ListItem Value="ASC" Text="Ascending" Selected="True" />
              <asp:ListItem Value="DESC" Text="Descending" />
            </asp:DropDownList>
          </td>
        </tr>
        <tr>
          <td>Then by:</td>
          <td>
            <asp:DropDownList ID="SortList2" runat="server">
              <asp:ListItem>ContactID</asp:ListItem>
              <asp:ListItem>FirstName</asp:ListItem>
              <asp:ListItem Selected="true">LastName</asp:ListItem>
              <asp:ListItem>EmailAddress</asp:ListItem>
            </asp:DropDownList>
          </td>
          <td>Sort order:</td>
          <td>
            <asp:DropDownList ID="DirectionList2" runat="server">
              <asp:ListItem Value="ASC" Text="Ascending" Selected="True" />
              <asp:ListItem Value="DESC" Text="Descending" />
            </asp:DropDownList>
          </td>
        </tr>
      </table>

      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        runat="server" onsorting="ContactsListView_Sorting">
        <LayoutTemplate>
          <asp:Button id="SortButton"
            Text="Sort"
            CommandName="Sort"
            runat="server"/>  

          <br/><br />

          <table cellpadding="2" width="640px" border="1" runat="server" id="tblContacts">
            <tr runat="server">
              <th runat="server">ContactID</th>
              <th runat="server">FirstName</th>
              <th runat="server">LastName</th>
              <th runat="server">EmailAddress</th>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ContactsDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowFirstPageButton="true" 
                ShowLastPageButton="true" />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%#Eval("ContactID") %>' />
            </td>
            <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="EmailAddressLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
      </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">        

  Sub ContactsListView_Sorting(ByVal sender As Object, ByVal e As ListViewSortEventArgs)
    
    ' Create the sort expression from the values selected 
    ' by the user from the DropDownList controls. Multiple
    ' columns can be sorted by creating a sort expression
    ' that contains a comma-separated list of field names
    ' and optionally directions for each column.
    e.SortExpression = SortList1.SelectedValue & " " & _
      DirectionList1.SelectedValue & " ," & SortList2.SelectedValue
    
    ' Determine the sort direction of the second column.
    ' The sort direction parameter applies only to the 
    ' last column sorted.
    e.SortDirection = SortDirection.Ascending
    If DirectionList2.SelectedValue = "DESC" Then
      e.SortDirection = SortDirection.Descending
    End If
    
  End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server"> 
    <title>SortExpression Example</title>
    <style type="text/css">
      body {  font: 10pt Trebuchet MS; }
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
          
      <h3>SortExpression Example</h3>

      <table>
        <tr>
          <td>Sort by:</td>
          <td>
            <asp:DropDownList ID="SortList1" runat="server">
              <asp:ListItem>ContactID</asp:ListItem>
              <asp:ListItem Selected="true">FirstName</asp:ListItem>
              <asp:ListItem>LastName</asp:ListItem>
              <asp:ListItem>EmailAddress</asp:ListItem>              
            </asp:DropDownList>
          </td>
          <td>Sort order:</td>
          <td>
            <asp:DropDownList ID="DirectionList1" runat="server">
              <asp:ListItem Value="ASC" Text="Ascending" Selected="True" />
              <asp:ListItem Value="DESC" Text="Descending" />
            </asp:DropDownList>
          </td>
        </tr>
        <tr>
          <td>Then by:</td>
          <td>
            <asp:DropDownList ID="SortList2" runat="server">
              <asp:ListItem>ContactID</asp:ListItem>
              <asp:ListItem>FirstName</asp:ListItem>
              <asp:ListItem Selected="true">LastName</asp:ListItem>
              <asp:ListItem>EmailAddress</asp:ListItem>
            </asp:DropDownList>
          </td>
          <td>Sort order:</td>
          <td>
            <asp:DropDownList ID="DirectionList2" runat="server">
              <asp:ListItem Value="ASC" Text="Ascending" Selected="True" />
              <asp:ListItem Value="DESC" Text="Descending" />
            </asp:DropDownList>
          </td>
        </tr>
      </table>

      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        runat="server" onsorting="ContactsListView_Sorting">
        <LayoutTemplate>
          <asp:Button id="SortButton"
            Text="Sort"
            CommandName="Sort"
            runat="server"/>  

          <br/><br />

          <table cellpadding="2" width="640px" border="1" runat="server" id="tblContacts">
            <tr runat="server">
              <th runat="server">ContactID</th>
              <th runat="server">FirstName</th>
              <th runat="server">LastName</th>
              <th runat="server">EmailAddress</th>
            </tr>
            <tr runat="server" id="itemPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ContactsDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField ButtonType="Button"
                ShowFirstPageButton="true" 
                ShowLastPageButton="true" />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td>
              <asp:Label ID="ContactIDLabel" runat="server" Text='<%#Eval("ContactID") %>' />
            </td>
            <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="EmailAddressLabel" runat="server" Text='<%#Eval("EmailAddress") %>' />
            </td>
          </tr>
        </ItemTemplate>
      </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>

Sorting При возникновении события можно использовать SortExpression свойство для указания выражения сортировки, которое будет использоваться для сортировки ListView элемента управления. Выражение сортировки содержит имя поля для сортировки. Вы также можете отсортировать несколько столбцов одновременно, задав это свойство в список имен полей, разделенных запятыми.

Замечание

По умолчанию ListView элемент управления применяет направление сортировки к полному списку столбцов. В результате направление сортировки применяется только к последнему столбцу в списке.

Применяется к

См. также раздел

Обратная связь

Были ли сведения на этой странице полезными?

Поделиться через