UnaryExpression UnaryExpression UnaryExpression UnaryExpression Class

Definition

Represents an expression that has a unary operator.

public ref class UnaryExpression sealed : System::Linq::Expressions::Expression
public sealed class UnaryExpression : System.Linq.Expressions.Expression
type UnaryExpression = class
    inherit Expression
Public NotInheritable Class UnaryExpression
Inherits Expression
Inheritance
UnaryExpressionUnaryExpressionUnaryExpressionUnaryExpression

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
// 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?));

Console.WriteLine(typeAsExpression.ToString());

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

Console.WriteLine(typeAsExpression.ToString())

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

Remarks

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

NodeType Factory Method
ArrayLength ArrayLength
Convert Convert
ConvertChecked ConvertChecked
Negate Negate
NegateChecked NegateChecked
Not Not
Quote Quote
TypeAs TypeAs
UnaryPlus UnaryPlus

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.

Properties

CanReduce CanReduce CanReduce CanReduce

Gets a value that indicates whether the expression tree node can be reduced.

IsLifted IsLifted IsLifted IsLifted

Gets a value that indicates whether the expression tree node represents a lifted call to an operator.

IsLiftedToNull IsLiftedToNull IsLiftedToNull 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.

Method Method Method Method

Gets the implementing method for the unary operation.

NodeType NodeType NodeType NodeType

Returns the node type of this Expression.

Operand Operand Operand Operand

Gets the operand of the unary operation.

Type Type Type Type

Gets the static type of the expression that this Expression represents.

Methods

Accept(ExpressionVisitor) Accept(ExpressionVisitor) Accept(ExpressionVisitor) Accept(ExpressionVisitor)

Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall(MethodCallExpression).

(Inherited from Expression)
Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
Reduce() Reduce() Reduce() Reduce()

Reduces the expression node to a simpler expression.

ReduceAndCheck() ReduceAndCheck() ReduceAndCheck() 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)
ReduceExtensions() ReduceExtensions() ReduceExtensions() 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)
ToString() ToString() ToString() ToString()

Returns a textual representation of the Expression.

(Inherited from Expression)
Update(Expression) Update(Expression) Update(Expression) Update(Expression)

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.

VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor) VisitChildren(ExpressionVisitor)

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)

Applies to