GridView.SortExpression GridView.SortExpression GridView.SortExpression GridView.SortExpression Property

Definición

Obtiene la expresión de ordenación asociada a la columna o columnas que se van a ordenar.Gets the sort expression associated with the column or columns being sorted.

public:
 virtual property System::String ^ SortExpression { System::String ^ get(); };
[System.ComponentModel.Browsable(false)]
public virtual string SortExpression { get; }
member this.SortExpression : string
Public Overridable ReadOnly Property SortExpression As String

Valor de propiedad

Expresión de ordenación asociada a la columna o columnas que se van a ordenar.The sort expression associated with the column or columns being sorted.

Ejemplos

En el ejemplo siguiente se muestra cómo utilizar SortExpression la propiedad para determinar el nombre de la columna que se está ordenando.The following example demonstrates how to use the SortExpression property to determine the name of the column being sorted.


<%@ 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">

  void CustomersGridView_RowCreated(Object sender, GridViewRowEventArgs e)
  {
    
    // Use the RowType property to determine whether the 
    // row being created is the header row. 
    if (e.Row.RowType == DataControlRowType.Header)
    {
      // Call the GetSortColumnIndex helper method to determine
      // the index of the column being sorted.
      int sortColumnIndex = GetSortColumnIndex();
      
      if (sortColumnIndex != -1)
      {
        // Call the AddSortImage helper method to add
        // a sort direction image to the appropriate
        // column header. 
        AddSortImage(sortColumnIndex, e.Row);
      }
    }
  }

  // This is a helper method used to determine the index of the
  // column being sorted. If no column is being sorted, -1 is returned.
  int GetSortColumnIndex()
  {

    // Iterate through the Columns collection to determine the index
    // of the column being sorted.
    foreach (DataControlField field in CustomersGridView.Columns)
    {
      if (field.SortExpression == CustomersGridView.SortExpression)
      {
        return CustomersGridView.Columns.IndexOf(field);
      }
    }

    return -1;
  }

  // This is a helper method used to add a sort direction
  // image to the header of the column being sorted.
  void AddSortImage(int columnIndex, GridViewRow headerRow)
  {
    
    // Create the sorting image based on the sort direction.
    Image sortImage = new Image();
    if (CustomersGridView.SortDirection == SortDirection.Ascending)
    {
      sortImage.ImageUrl = "~/Images/Ascending.jpg";
      sortImage.AlternateText = "Ascending Order";
    }
    else
    {
      sortImage.ImageUrl = "~/Images/Descending.jpg";
      sortImage.AlternateText = "Descending Order";
    }

    // Add the image to the appropriate header cell.
    headerRow.Cells[columnIndex].Controls.Add(sortImage);
    
  }
    
</script>

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

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSource" 
        autogeneratecolumns="false"
        emptydatatext="No data available." 
        allowsorting="true"
        onrowcreated="CustomersGridView_RowCreated"
        runat="server">
        
        <columns>
          <asp:boundfield datafield="CustomerID"
            headertext="Customer ID"
            headerstyle-wrap="false" 
            sortexpression="CustomerID"/>
          <asp:boundfield datafield="CompanyName"
            headertext="CompanyName"
            headerstyle-wrap="false"
            sortexpression="CompanyName"/>
          <asp:boundfield datafield="Address"
            headertext="Address"
            headerstyle-wrap="false"
            sortexpression="Address"/>
          <asp:boundfield datafield="City"
            headertext="City"
            headerstyle-wrap="false"
            sortexpression="City"/>
          <asp:boundfield datafield="PostalCode"
            headertext="Postal Code"
            headerstyle-wrap="false"
            sortexpression="PostalCode" />
          <asp:boundfield datafield="Country"
            headertext="Country"
            headerstyle-wrap="false"
            sortexpression="Country"/>         
        </columns>
                
      </asp:gridview>
            
      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the Web.config file.                            -->
      <asp:sqldatasource id="CustomersSource"
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
        
    </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 CustomersGridView_RowCreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    
    ' Use the RowType property to determine whether the 
    ' row being created is the header row. 
    If e.Row.RowType = DataControlRowType.Header Then
    
      ' Call the GetSortColumnIndex helper method to determine
      ' the index of the column being sorted.
      Dim sortColumnIndex As Integer = GetSortColumnIndex()
      
      If sortColumnIndex <> -1 Then
      
        ' Call the AddSortImage helper method to add
        ' a sort direction image to the appropriate
        ' column header. 
        AddSortImage(sortColumnIndex, e.Row)
    
      End If
      
    End If
    
  End Sub

  ' This is a helper method used to determine the index of the
  ' column being sorted. If no column is being sorted, -1 is returned.
  Function GetSortColumnIndex() As Integer

    ' Iterate through the Columns collection to determine the index
    ' of the column being sorted.
    Dim field As DataControlField
    For Each field In CustomersGridView.Columns
    
      If field.SortExpression = CustomersGridView.SortExpression Then
      
        Return CustomersGridView.Columns.IndexOf(field)

      End If
      
    Next

    Return -1
      
  End Function

  ' This is a helper method used to add a sort direction
  ' image to the header of the column being sorted.
  Sub AddSortImage(ByVal columnIndex As Integer, ByVal row As GridViewRow)

    ' Create the sorting image based on the sort direction.
    Dim sortImage As New Image()
    If CustomersGridView.SortDirection = SortDirection.Ascending Then
    
      sortImage.ImageUrl = "~/Images/Ascending.jpg"
      sortImage.AlternateText = "Ascending Order"
    
    Else
    
      sortImage.ImageUrl = "~/Images/Descending.jpg"
      sortImage.AlternateText = "Descending Order"
    
    End If
    ' Add the image to the appropriate header cell.
    row.Cells(columnIndex).Controls.Add(sortImage)
    
  End Sub
    
</script>

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

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSource" 
        autogeneratecolumns="false"
        emptydatatext="No data available." 
        allowsorting="true"
        onrowcreated="CustomersGridView_RowCreated"
        runat="server">
        
        <columns>
          <asp:boundfield datafield="CustomerID"
            headertext="Customer ID"
            headerstyle-wrap="false" 
            sortexpression="CustomerID"/>
          <asp:boundfield datafield="CompanyName"
            headertext="CompanyName"
            headerstyle-wrap="false"
            sortexpression="CompanyName"/>
          <asp:boundfield datafield="Address"
            headertext="Address"
            headerstyle-wrap="false"
            sortexpression="Address"/>
          <asp:boundfield datafield="City"
            headertext="City"
            headerstyle-wrap="false"
            sortexpression="City"/>
          <asp:boundfield datafield="PostalCode"
            headertext="Postal Code"
            headerstyle-wrap="false"
            sortexpression="PostalCode" />
          <asp:boundfield datafield="Country"
            headertext="Country"
            headerstyle-wrap="false"
            sortexpression="Country"/>         
        </columns>
                
      </asp:gridview>
            
      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the Web.config file.                            -->
      <asp:sqldatasource id="CustomersSource"
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
        
    </form>
  </body>
</html>

Comentarios

Utilice la SortExpression propiedad para determinar la expresión de ordenación asociada a la columna o columnas que se están ordenando.Use the SortExpression property to determine the sort expression associated with the column or columns being sorted.

Nota

El GridView control tiene una característica de ordenación integrada que establece automáticamente esta propiedad.The GridView control has a built-in sorting feature that automatically sets this property. Esta propiedad se usa normalmente solo cuando es necesario determinar mediante programación la columna o columnas que se están ordenando o cuando se agrega su propia funcionalidad de ordenación personalizada a GridView un control.This property is typically used only when you need to programmatically determine the column or columns being sorted or when you are adding your own custom sorting functionality to a GridView control.

Cuando se ordenan varias columnas, esta propiedad contiene una lista separada por comas de los campos por los que se va a ordenar.When multiple columns are sorted, this property contains a comma-separated list of the fields by which to sort.

Se aplica a

Consulte también: