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OrderByExpression Class

Provides a way to apply a sort expression to an IQueryable object.

System.Object
  System.Web.UI.WebControls.Expressions.DataSourceExpression
    System.Web.UI.WebControls.Expressions.OrderByExpression

Namespace:  System.Web.UI.WebControls.Expressions
Assembly:  System.Web.Extensions (in System.Web.Extensions.dll)
public class OrderByExpression : DataSourceExpression

The OrderByExpression type exposes the following members.

  NameDescription
Public methodOrderByExpressionInitializes a new instance of the OrderByExpression class.
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  NameDescription
Protected propertyContextGets the HttpContext instance of the owner control. (Inherited from DataSourceExpression.)
Public propertyDataFieldGets or sets the property of the IQueryable object to sort by.
Public propertyDataSourceGets the data source object that is associated with the owner control. (Inherited from DataSourceExpression.)
Public propertyDirectionGets and sets the sort direction of the IQueryable data source object.
Protected propertyIsTrackingViewStateGets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression.)
Protected propertyOwnerGets the owner control. (Inherited from DataSourceExpression.)
Public propertyThenByExpressionsGets or sets the collection of ThenBy expressions to apply after an OrderByExpression value is applied to the data source.
Protected propertyViewStateGets an instance of the StateBag class that contains the current view state information. (Inherited from DataSourceExpression.)
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetQueryableApplies a sort expression to an IQueryable object based on a DataField value and a Direction value. (Overrides DataSourceExpression.GetQueryable(IQueryable).)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodLoadViewStateLoads the state of the values in the DataSourceExpression object that must be persisted. (Inherited from DataSourceExpression.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodSaveViewStateSaves the current view state of the DataSourceExpression object. (Inherited from DataSourceExpression.)
Public methodSetContextSets the HTTP context of the DataSourceExpression object that uses the specified owner control, HttpContext instance, and IQueryableDataSource object. (Inherited from DataSourceExpression.)
Public methodSetDirtyMarks the DataSourceExpression object so that its state will be saved in view state. (Inherited from DataSourceExpression.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Protected methodTrackViewStateTracks view state changes of the DataSourceExpression object so that the changes can be stored in the StateBag object for the data source expression object. (Inherited from DataSourceExpression.)
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  NameDescription
Explicit interface implemetationPrivate propertyIStateManager.IsTrackingViewStateWhen implemented by a class, gets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.LoadViewStateWhen implemented by a class, loads the previously saved view state of the data source expression object. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.SaveViewStateWhen implemented by a class, saves the current view state of the DataSourceExpression object. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.TrackViewStateWhen implemented by a class, tracks view state changes of the DataSourceExpression object so that the changes can be stored in the StateBag object for the data source expression object. (Inherited from DataSourceExpression.)
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ExceptionCondition
InvalidOperationException

The DataField property is null.

The OrderByExpression class is used in the QueryExtender control to sort data in ascending or descending order. The sorting is performed by the default comparer for the type of the element.

The QueryExtender control supports a variety of options that you can use to filter data. After you use the filter options, you can use the OrderByExpression object to sort the data.

You specify the data field to sort by using the DataField property. You specify the sort direction by using the Direction property. After the OrderByExpression object has been applied to the data source, you can use the ThenBy expressions to perform a subsequent sort on another data field.

The following example shows how to search the Products table of the AdventureWorks database for products that have names that start with the string that is specified in the SearchTextBox text box. The OrderByExpression object sorts the data by the ListPrice data field in descending order and then by the product ID field in ascending order. The result of the query that is returned from the LinqDataSource control is displayed in a GridView control.

This code example is part of a larger example that is provided in Walkthrough: Filtering Data in a Web Page Using Declarative Syntax.

<form id="form1" runat="server">
    Search:<asp:TextBox ID="SearchTextBox" runat="server" />
  <p>
    <asp:Button ID="Button1" runat="server" Text="Search"  />
  </p>

  <asp:LinqDataSource ID="LinqDataSource1"  
      ContextTypeName="AdventureWorksDataContext"  
      TableName="Products" runat="server"> 
  </asp:LinqDataSource>

  <asp:QueryExtender runat="server" TargetControlID="LinqDataSource1">
    <asp:SearchExpression SearchType="StartsWith" DataFields="Name" >
      <asp:ControlParameter ControlID="SearchTextBox" />
    </asp:SearchExpression>
    <asp:OrderByExpression DataField="ListPrice" 
        Direction="Descending">
      <asp:ThenBy DataField="ProductID" Direction="Ascending"/>
    </asp:OrderByExpression>
  </asp:QueryExtender>

  <asp:GridView ID="GridView1" runat="server"  
      DataSourceID="LinqDataSource1" AllowPaging="True" >
  </asp:GridView>
</form>

.NET Framework

Supported in: 4.5.1, 4.5, 4

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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