Редагувати

Поділитися через


NewExpression Class

Definition

Represents a constructor call.

public ref class NewExpression : System::Linq::Expressions::Expression, System::Linq::Expressions::IArgumentProvider
public ref class NewExpression sealed : System::Linq::Expressions::Expression
public ref class NewExpression : System::Linq::Expressions::Expression
public class NewExpression : System.Linq.Expressions.Expression, System.Linq.Expressions.IArgumentProvider
public sealed class NewExpression : System.Linq.Expressions.Expression
public class NewExpression : System.Linq.Expressions.Expression
type NewExpression = class
    inherit Expression
    interface IArgumentProvider
type NewExpression = class
    inherit Expression
Public Class NewExpression
Inherits Expression
Implements IArgumentProvider
Public NotInheritable Class NewExpression
Inherits Expression
Public Class NewExpression
Inherits Expression
Inheritance
NewExpression
Implements

Examples

The following example creates a NewExpression that represents the construction of a new instance of a dictionary object.

// Create a NewExpression that represents constructing
// a new instance of Dictionary<int, string>.
System.Linq.Expressions.NewExpression newDictionaryExpression =
    System.Linq.Expressions.Expression.New(typeof(Dictionary<int, string>));

Console.WriteLine(newDictionaryExpression.ToString());

// This code produces the following output:
//
// new Dictionary`2()
' Create a NewExpression that represents constructing
' a new instance of Dictionary(Of Integer, String).
Dim newDictionaryExpression As System.Linq.Expressions.NewExpression = _
    System.Linq.Expressions.Expression.[New]( _
        Type.GetType("System.Collections.Generic.Dictionary`2[System.Int32, System.String]"))

Console.WriteLine(newDictionaryExpression.ToString())

' This code produces the following output:
'
' new Dictionary`2()

Remarks

Use the New factory methods to create a NewExpression.

The value of the NodeType property of a NewExpression object is New.

Properties

Arguments

Gets the arguments to the constructor.

CanReduce

Indicates that the node can be reduced to a simpler node. If this returns true, Reduce() can be called to produce the reduced form.

(Inherited from Expression)
Constructor

Gets the called constructor.

Members

Gets the members that can retrieve the values of the fields that were initialized with constructor arguments.

NodeType

Returns the node type of this Expression.

NodeType

Gets the node type of this Expression.

(Inherited from Expression)
Type

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

Type

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

(Inherited from Expression)

Methods

Accept(ExpressionVisitor)

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

Accept(ExpressionVisitor)

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

(Inherited from Expression)
Equals(Object)

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

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
Reduce()

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)
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()

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()

Returns a textual representation of the Expression.

(Inherited from Expression)
Update(IEnumerable<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)

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)

Explicit Interface Implementations

IArgumentProvider.ArgumentCount

Gets the number of arguments to the expression tree node.

IArgumentProvider.GetArgument(Int32)

Returns the argument at index, throwing if index is out of bounds.

Applies to