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DbExpressionBuilder.CreateRef Method (EntitySet, EntityType, IEnumerable<DbExpression>)

.NET Framework 4.5

Creates a new DbRefExpression that encodes a reference to a specific entity of a given type based on key values.

Namespace:  System.Data.Common.CommandTrees.ExpressionBuilder
Assembly:  System.Data.Entity (in System.Data.Entity.dll)
public static DbRefExpression CreateRef(
	this EntitySet entitySet,
	EntityType entityType,
	IEnumerable<DbExpression> keyValues


Type: System.Data.Metadata.Edm.EntitySet

The entity set in which the referenced element resides.

Type: System.Data.Metadata.Edm.EntityType

The specific type of the referenced entity. This must be an entity type from the same hierarchy as the entity set's element type.

Type: System.Collections.Generic.IEnumerable<DbExpression>

A collection of DbExpressions that provide the key values. These expressions must match (in number, type, and order) the key properties of the referenced entity type.

Return Value

Type: System.Data.Common.CommandTrees.DbRefExpression
A new DbRefExpression that references the element with the specified key values in the given entity set.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type EntitySet. 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).

entitySet or entityType is null, or keyValues is null or contains null.


entityType is not from the same type hierarchy (a subtype, supertype, or the same type) as entitySet's element type.


The count of keyValues does not match the count of key members declared by the entitySet’s element type, or keyValues contains an expression with a result type that is not compatible with the type of the corresponding key member.

.NET Framework

Supported in: 4.5.1, 4.5

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.

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