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Expression.UnaryPlus Method (Expression, MethodInfo)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Creates a UnaryExpression that represents a unary plus operation.

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

Syntax

'Declaration
Public Shared Function UnaryPlus ( _
    expression As Expression, _
    method As MethodInfo _
) As UnaryExpression

public static UnaryExpression UnaryPlus(
    Expression expression,
    MethodInfo method
)

Parameters

Return Value

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

Exceptions

Exception Condition
ArgumentNullException

expression is nulla null reference (Nothing in Visual Basic).
ArgumentException

method is not nulla null reference (Nothing in Visual Basic) and the method it represents returns void, is not static (Shared in Visual Basic), or does not take exactly one argument.
InvalidOperationException

method is nulla null reference (Nothing in Visual Basic) and the unary plus 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.

Remarks

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.

Implementing Method

The following rules determine the implementing method for the operation:

  • If method is not nulla null reference (Nothing in Visual Basic) 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 plus operator, the MethodInfo that represents that operator is the implementing method.

  • Otherwise, if expression.Type is a numeric type, the implementing method is nulla null reference (Nothing in Visual Basic).

Node Type and Lifted versus Non-Lifted

If the implementing method is not nulla null reference (Nothing in Visual Basic):

  • 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 nulla null reference (Nothing in Visual Basic), the type of the node is expression.Type. If expression.Type is non-nullable, the node is not lifted. Otherwise, the node is lifted.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.