DbExpressionBuilder.OfType Method (DbExpression, TypeUsage)

.NET Framework (current version)

Creates a new DbOfTypeExpression that produces a set consisting of the elements of the given input set that are of the specified type.

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

public static DbOfTypeExpression OfType(
	this DbExpression argument,
	TypeUsage type


Type: System.Data.Common.CommandTrees.DbExpression

A DbExpression that specifies the input set.

Type: System.Data.Metadata.Edm.TypeUsage

Type metadata for the type that elements of the input set must have to be included in the resulting set.

Return Value

Type: System.Data.Common.CommandTrees.DbOfTypeExpression

A new DbOfTypeExpression with the specified set argument and type, and an ExpressionKind of OfType.

Exception Condition

argument or type is null.


argument does not have a collection result type, or type is not a type in the same type hierarchy as the element type of the collection result type of argument.

DbOfTypeExpression requires that argument has a collection result type with a polymorphic element type, and that type is a type from the same type hierarchy as that element type.

.NET Framework
Available since 4.5
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