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Expression.Negate Method (Expression, MethodInfo)

Creates a UnaryExpression that represents an arithmetic negation operation.

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

public static UnaryExpression Negate(
	Expression expression,
	MethodInfo method
)

Parameters

expression
Type: System.Linq.Expressions.Expression

An Expression to set the Operand property equal to.

method
Type: System.Reflection.MethodInfo

A MethodInfo to set the Method property equal to.

Return Value

Type: System.Linq.Expressions.UnaryExpression
A UnaryExpression that has the NodeType property equal to Negate and the Operand and Method properties set to the specified values.

ExceptionCondition
ArgumentNullException

expression is null.

ArgumentException

method is not null and the method it represents returns void, is not static (Shared in Visual Basic), or does not take exactly one argument.

InvalidOperationException

method is null and the unary minus operator is not defined for expression.Type.

-or-

expression.Type (or its corresponding non-nullable type if it is a nullable value type) is not assignable to the argument type of the method represented by method.

The Method property of the resulting UnaryExpression is set to the implementing method. The Type property is set to the type of the node. If the node is lifted, the IsLifted and IsLiftedToNull properties are both true. Otherwise, they are false.

The following rules determine the implementing method for the operation:

  • If method is not null and it represents a non-void, static (Shared in Visual Basic) method that takes one argument, it is the implementing method for the node.

  • If expression.Type is a user-defined type that defines the unary minus operator, the MethodInfo that represents that operator is the implementing method.

  • Otherwise, if expression.Type is a numeric type, the implementing method is null.

If the implementing method is not null:

  • If expression.Type is assignable to the argument type 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 and the type of the node is the nullable type that corresponds to the return type of the implementing method:

    • expression.Type is a nullable value type and the corresponding non-nullable value type is equal to the argument type of the implementing method.

    • The return type of the implementing method is a non-nullable value type.

If the implementing method is null, the type of the node is expression.Type. If expression.Type is non-nullable, the node is not lifted. Otherwise, the node is lifted.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

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

Portable Class Library

Supported in: Portable Class Library
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