UnaryExpression Class

Represents an expression that has a unary operator.

Inheritance Hierarchy

System.Object
  System.Linq.Expressions.Expression
    System.Linq.Expressions.UnaryExpression

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

Syntax

'Declaration
Public NotInheritable Class UnaryExpression _
    Inherits Expression
public sealed class UnaryExpression : Expression

The UnaryExpression type exposes the following members.

Properties

  Name Description
Public property CanReduce Gets a value that indicates whether the expression tree node can be reduced. (Overrides Expression.CanReduce.)
Public propertySupported by Silverlight for Windows Phone IsLifted Gets a value that indicates whether the expression tree node represents a lifted call to an operator.
Public propertySupported by Silverlight for Windows Phone IsLiftedToNull Gets a value that indicates whether the expression tree node represents a lifted call to an operator whose return type is lifted to a nullable type.
Public propertySupported by Silverlight for Windows Phone Method Gets the implementing method for the unary operation.
Public propertySupported by Silverlight for Windows Phone NodeType Returns the node type of this Expression. (Overrides Expression.NodeType.)

In Silverlight for Windows Phone Windows Phone OS 7.1, this member is inherited from Expression.NodeType.

In XNA Framework Windows Phone OS 7.0, this member is inherited from Expression.NodeType.
Public propertySupported by Silverlight for Windows Phone Operand Gets the operand of the unary operation.
Public propertySupported by Silverlight for Windows Phone Type Gets the static type of the expression that this Expression represents. (Overrides Expression.Type.)

In Silverlight for Windows Phone Windows Phone OS 7.1, this member is inherited from Expression.Type.

In XNA Framework Windows Phone OS 7.0, this member is inherited from Expression.Type.

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Methods

  Name Description
Protected method Accept Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Inherited from Expression.)
Public methodSupported by Silverlight for Windows Phone Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone Finalize Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by Silverlight for Windows Phone GetType Gets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows Phone MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method Reduce Reduces the expression node to a simpler expression. (Overrides Expression.Reduce().)
Public method ReduceAndCheck Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced. (Inherited from Expression.)
Public method ReduceExtensions Reduces the expression to a known node type (that is not an Extension node) or just returns the expression if it is already a known type. (Inherited from Expression.)
Public methodSupported by Silverlight for Windows Phone ToString Returns a textual representation of the Expression. (Inherited from Expression.)
Public method Update Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will return this expression.
Protected method VisitChildren Reduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible. (Inherited from Expression.)

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Remarks

The following table summarizes the factory methods that can be used to create a UnaryExpression that has a specific node type.

In addition, the MakeUnary methods can also be used to create a UnaryExpression. These factory methods can be used to create a UnaryExpression of any node type that represents a unary operation. The parameter of these methods that is of type NodeType specifies the desired node type.

Examples

The following example creates a UnaryExpression object that represents the reference conversion of a non-nullable integer expression to the nullable integer type.

' Create a UnaryExpression that represents a reference
' conversion of an Integer to an Integer? (a nullable Integer).
Dim typeAsExpression As System.Linq.Expressions.UnaryExpression = _
    System.Linq.Expressions.Expression.TypeAs( _
        System.Linq.Expressions.Expression.Constant(34, Type.GetType("System.Int32")), _
        Type.GetType("System.Nullable`1[System.Int32]"))

outputBlock.Text &= typeAsExpression.ToString() & vbCrLf

' This code produces the following output:
'
' (34 As Nullable`1)
// Create a UnaryExpression that represents a
// conversion of an int to an int?.
System.Linq.Expressions.UnaryExpression typeAsExpression =
    System.Linq.Expressions.Expression.TypeAs(
        System.Linq.Expressions.Expression.Constant(34, typeof(int)),
        typeof(int?));

outputBlock.Text += typeAsExpression.ToString() + "\n";

// This code produces the following output:
//
// (34 As Nullable`1)

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.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.