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DbExpressionBuilder.SelectMany Method (DbExpression, Func<DbExpression, DbExpression>)

.NET Framework 4.5

Creates a new DbApplyExpression that evaluates the given apply expression once for each element of a given input set, producing a collection of rows with corresponding input and apply columns. Rows for which apply evaluates to an empty set are not included. A DbProjectExpression is then created that selects the apply column from each row, producing the overall collection of apply results.

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

public static DbProjectExpression SelectMany(
	this DbExpression source,
	Func<DbExpression, DbExpression> apply


Type: System.Data.Common.CommandTrees.DbExpression

A DbExpression that specifies the input set.

Type: System.Func<DbExpression, DbExpression>

A method that represents the logic to evaluate once for each member of the input set.

Return Value

Type: System.Data.Common.CommandTrees.DbProjectExpression
An new DbProjectExpression that selects the apply column from a new DbApplyExpression with the specified input and apply bindings and an DbExpressionKind of CrossApply.

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 or apply is null.


The expression produced by apply is null.


source does not have a collection result type.


The expression produced by apply does not have a collection type.

.NET Framework

Supported in: 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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