DefaultExpression Sınıf

Tanım

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

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

type DefaultExpression = class
    inherit Expression

Public NotInheritable Class DefaultExpression
Inherits Expression

Devralma

Object

Expression

DefaultExpression

Örnekler

Aşağıdaki kod örneği, yöntemini kullanarak belirli bir tür için varsayılan değeri temsil eden bir ifadenin Default nasıl oluşturulacağını gösterir.

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

// This expression represents the default value of a type
// (0 for integer, null for a string, etc.)
Expression defaultExpr = Expression.Default(
                            typeof(byte)
                        );

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

// The following statement first creates an expression tree,
// then compiles it, and then executes it.
Console.WriteLine(
    Expression.Lambda<Func<byte>>(defaultExpr).Compile()());

// This code example produces the following output:
//
// default(Byte)
// 0

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

' This expression represents the default value of a type
' (0 for integer, null for a string, and so on).
Dim defaultExpr As Expression = Expression.Default(
                                        GetType(Byte)
                                    )

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

' The following statement first creates an expression tree,
' then compiles it, and then executes it.
Console.WriteLine(
    Expression.Lambda(Of Func(Of Byte))(defaultExpr).Compile()())

' This code example produces the following output:
'
' default(Byte)
' 0

Özellikler

Yöntemler

Şunlara uygulanır