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DbExpressionBuilder.OfType Method

.NET Framework 4.5

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.

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).


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

Supported in: 4.6, 4.5
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