DbExpressionBuilder::CreateRef Method (EntitySet^, EntityType^, IEnumerable<DbExpression^>^)
Creates a new DbRefExpression that encodes a reference to a specific entity of a given type based on key values.
Assembly: System.Data.Entity (in System.Data.Entity.dll)
public: [ExtensionAttribute] static DbRefExpression^ CreateRef( EntitySet^ entitySet, EntityType^ entityType, IEnumerable<DbExpression^>^ keyValues )
Parameters
- entitySet
-
Type:
System.Data.Metadata.Edm::EntitySet^
The entity set in which the referenced element resides.
- entityType
-
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.
- keyValues
-
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.
| Exception | Condition |
|---|---|
| ArgumentNullException | entitySet or entityType is null, or keyValues is null or contains null. |
| ArgumentException | entityType is not from the same type hierarchy (a subtype, supertype, or the same type) as entitySet's element type. |
| ArgumentException | 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. |
Available since 4.5