ConstantExpression Class

Definition

Namespace:

System.Linq.Expressions

Assembly:

System.Linq.Expressions.dll

Source:

ConstantExpression.cs

Represents an expression that has a constant value.

public ref class ConstantExpression : System::Linq::Expressions::Expression

public class ConstantExpression : System.Linq.Expressions.Expression

type ConstantExpression = class
    inherit Expression

Public Class ConstantExpression
Inherits Expression

Inheritance

Object

Expression

ConstantExpression

Examples

The following code example shows how to create an expression that represents a constant value by using the Constant method.

// Add the following directive to your file:
// using System.Linq.Expressions;

// This expression represents a Constant value.
Expression constantExpr = Expression.Constant(5.5);

// Print out the expression.
Console.WriteLine(constantExpr.ToString());

// You can also use variables.
double num = 3.5;
constantExpr = Expression.Constant(num);
Console.WriteLine(constantExpr.ToString());

// This code example produces the following output:
//
// 5.5
// 3.5

' Add the following directive to your file:
' Imports System.Linq.Expressions 

' This expression represents a constant value.
Dim constantExpr As Expression = Expression.Constant(5.5)

' Print the expression.
Console.WriteLine(constantExpr.ToString())

' You can also use variables.
Dim num As Double = 3.5
constantExpr = Expression.Constant(num)
Console.WriteLine(constantExpr.ToString())

' This code example produces the following output:
'
' 5.5
' 3.5

Remarks

Use the Constant factory methods to create a ConstantExpression.

The NodeType of a ConstantExpression is Constant.

Properties

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)
NodeType	Returns the node type of this Expression. Extension nodes should return Extension when overriding this method.
Type	Gets the static type of the expression that this Expression represents.
Value	Gets the value of the constant expression.

Methods

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