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Expression.LessThan Method (Expression, Expression, Boolean, MethodInfo)

Creates a BinaryExpression that represents a "less than" numeric comparison.

Namespace:  System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

'Declaration
Public Shared Function LessThan ( _
	left As Expression, _
	right As Expression, _
	liftToNull As Boolean, _
	method As MethodInfo _
) As BinaryExpression

Parameters

left
Type: System.Linq.Expressions.Expression

An Expression to set the Left property equal to.

right
Type: System.Linq.Expressions.Expression

An Expression to set the Right property equal to.

liftToNull
Type: System.Boolean

true to set IsLiftedToNull to true; false to set IsLiftedToNull to false.

method
Type: System.Reflection.MethodInfo

A MethodInfo to set the Method property equal to.

Return Value

Type: System.Linq.Expressions.BinaryExpression
A BinaryExpression that has the NodeType property equal to LessThan and the Left, Right, IsLiftedToNull, and Method properties set to the specified values.

ExceptionCondition
ArgumentNullException

left or right is Nothing.

ArgumentException

method is not Nothing and the method it represents returns void, is not static (Shared in Visual Basic), or does not take exactly two arguments.

InvalidOperationException

method is Nothing and the "less than" operator is not defined for left.Type and right.Type.

The resulting BinaryExpression has the Method property set to the implementing method. The Type property is set to the type of the node. If the node is lifted, the IsLifted property is true and the IsLiftedToNull property is equal to liftToNull. Otherwise, they are both false. The Conversion property is Nothing.

The following information describes the implementing method, the node type, and whether a node is lifted.

The following rules determine the implementing method for the operation:

  • If method is not Nothing and it represents a non-void, static (Shared in Visual Basic) method that takes two arguments, it is the implementing method.

  • Otherwise, if the Type property of either left or right represents a user-defined type that overloads the "less than" operator, the MethodInfo that represents that method is the implementing method.

  • Otherwise, if left.Type and right.Type are numeric types, the implementing method is Nothing.

If the implementing method is not Nothing:

  • If left.Type and right.Type are assignable to the corresponding argument types of the implementing method, the node is not lifted. The type of the node is the return type of the implementing method.

  • If the following two conditions are satisfied, the node is lifted; also, the type of the node is nullable Boolean if liftToNull is true or Boolean if liftToNull is false:

    • left.Type and right.Type are both value types of which at least one is nullable and the corresponding non-nullable types are equal to the corresponding argument types of the implementing method.

    • The return type of the implementing method is Boolean.

If the implementing method is Nothing:

  • If left.Type and right.Type are both non-nullable, the node is not lifted. The type of the node is Boolean.

  • If left.Type and right.Type are both nullable, the node is lifted. The type of the node is nullable Boolean if liftToNull is true or Boolean if liftToNull is false.

.NET Framework

Supported in: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

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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