ParameterExpression Třída

Definice

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

public ref class ParameterExpression sealed : System::Linq::Expressions::Expression

public class ParameterExpression : System.Linq.Expressions.Expression

public sealed class ParameterExpression : System.Linq.Expressions.Expression

type ParameterExpression = class
    inherit Expression

Public Class ParameterExpression
Inherits Expression

Public NotInheritable Class ParameterExpression
Inherits Expression

Dědičnost

Object

Expression

ParameterExpression

Příklady

Následující příklad ukazuje, jak vytvořit MethodCallExpression objekt, který vytiskne hodnotu objektu ParameterExpression pomocí Parameter metody .

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

// Creating a parameter for the expression tree.
ParameterExpression param = Expression.Parameter(typeof(int));

// Creating an expression for the method call and specifying its parameter.
MethodCallExpression methodCall = Expression.Call(
    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(int) }),
    param
);

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
Expression.Lambda<Action<int>>(
    methodCall,
    new ParameterExpression[] { param }
).Compile()(10);

// This code example produces the following output:
//
// 10

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

' Creating a parameter for the expression tree.
Dim param As ParameterExpression = Expression.Parameter(GetType(Integer))

' Creating an expression for the method call and specifying its parameter.
Dim methodCall As MethodCallExpression = Expression.Call(
        GetType(Console).GetMethod("WriteLine", New Type() {GetType(Integer)}),
        param
    )

' Compiling and invoking the methodCall expression.
Expression.Lambda(Of Action(Of Integer))(
    methodCall,
    New ParameterExpression() {param}
).Compile()(10)
' This code example produces the following output:
'
' 10

Poznámky

K vytvoření objektu Parameter použijte metodu ParameterExpressionfactory .

Hodnota NodeType vlastnosti objektu ParameterExpression je Parameter.

Vlastnosti

Metody

Platí pro