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DbExpressionBuilder.OrderByDescending Method (DbExpression, Func<DbExpression, DbExpression>, String)

.NET Framework 4.5

Creates a new DbSortExpression that sorts the given input set by the specified sort key, with descending sort order and the specified collation.

Namespace:  System.Data.Common.CommandTrees.ExpressionBuilder
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public static DbSortExpression OrderByDescending(
	this DbExpression source,
	Func<DbExpression, DbExpression> sortKey,
	string collation


Type: System.Data.Common.CommandTrees.DbExpression

An expression that specifies the input set.

Type: System.Func<DbExpression, DbExpression>

A method that specifies how to derive the sort key expression given a member of the input set. This method must produce an expression with an order-comparable result type that provides the sort key definition.

Type: System.String

The collation to sort under.

Return Value

Type: System.Data.Common.CommandTrees.DbSortExpression
A new DbSortExpression that represents the order-by operation.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type DbExpression. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).


source, sortKey or collation is null.


The expression produced by sortKey is null.


source does not have a collection result type.


The expression produced by sortKey does not have an order-comparable string result type.


collation is empty or contains only space characters.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5

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.

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