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DbExpressionBuilder.IsOf Method

.NET Framework 4.5

Creates a new DbIsOfExpression that determines whether the given argument is of the specified type or a subtype.

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

public static DbIsOfExpression IsOf(
	this DbExpression argument,
	TypeUsage type


Type: System.Data.Common.CommandTrees.DbExpression

An expression that specifies the instance.

Type: System.Data.Metadata.Edm.TypeUsage

Type metadata that specifies the type that the instance's result type should be compared to.

Return Value

Type: System.Data.Common.CommandTrees.DbIsOfExpression
A new DbIsOfExpression with the specified instance and type and DbExpressionKind IsOf.

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.


type is not in the same type hierarchy as the result type of argument.

DbIsOfExpression requires that argument has a polymorphic result type, and that type is a type from the same type hierarchy as that result type.

.NET Framework

Supported in: 4.6, 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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