可选参数和InteropServices [英] Optional arguments and InteropServices

问题描述

我正在使用第一时间可选参数，但我无法理解这两个方法定义之间的区别:

I'm using for the firs time optional arguments but I cannot understand difference between those two method definitions:

private void method1([Optional, DefaultParameterValue(string.Empty)] string testString)
{
    //do something
}

private void method2(string testString = "")
{
    //do something
}

方法1的定义需要:

using System.Runtime.InteropServices;

Method2定义较小，不需要导入.

Method2 definition is smaller and needs no import.

在使用其中一种方法语法之前，我是否需要考虑一些问题?

Have I to consider something before using one of those method syntax?

推荐答案

从.NET 1.1开始存在方法1.

Method 1 was present since .NET 1.1.

方法2是C#4引入的(直到那时C#才支持可选参数).

Method 2 was introduced with C# 4 (C# did not support optional parameters until then).

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