UnaryExpression Class

 

Represents an expression that has a unary operator.

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

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

public sealed class UnaryExpression : Expression

NameDescription
System_CAPS_pubpropertyCanReduce

Gets a value that indicates whether the expression tree node can be reduced.(Overrides Expression.CanReduce.)

System_CAPS_pubpropertyIsLifted

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

System_CAPS_pubpropertyIsLiftedToNull

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.

System_CAPS_pubpropertyMethod

Gets the implementing method for the unary operation.

System_CAPS_pubpropertyNodeType

Returns the node type of this Expression.(Overrides Expression.NodeType.)

System_CAPS_pubpropertyOperand

Gets the operand of the unary operation.

System_CAPS_pubpropertyType

Gets the static type of the expression that this Expression represents.(Overrides Expression.Type.)

NameDescription
System_CAPS_protmethodAccept(ExpressionVisitor)

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

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodReduce()

Reduces the expression node to a simpler expression. (Overrides Expression.Reduce().)

System_CAPS_pubmethodReduceAndCheck()

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.)

System_CAPS_pubmethodReduceExtensions()

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.)

System_CAPS_pubmethodToString()

Returns a textual representation of the Expression.(Inherited from Expression.)

System_CAPS_pubmethodUpdate(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.

System_CAPS_protmethodVisitChildren(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.)

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.

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)

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

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

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