C# 中类似于 SQL 'in' 关键字的简写条件 [英] Shorthand conditional in C# similar to SQL 'in' keyword

问题描述

在 C# 中是否有一种简写方式:

In C# is there a shorthand way to write this:

public static bool IsAllowed(int userID)
{
    return (userID == Personnel.JohnDoe || userID == Personnel.JaneDoe ...);
}

喜欢:

public static bool IsAllowed(int userID)
{
    return (userID in Personnel.JohnDoe, Personnel.JaneDoe ...);
}

我知道我也可以使用 switch，但是我必须编写大约 50 个这样的函数(将经典的 ASP 站点移植到 ASP.NET)，所以我希望它们尽可能短.

I know I could also use switch, but there are probably 50 or so functions like this I have to write (porting a classic ASP site over to ASP.NET) so I'd like to keep them as short as possible.

推荐答案

这个怎么样?

public static class Extensions
{
    public static bool In<T>(this T testValue, params T[] values)
    {
        return values.Contains(testValue);
    }
}

用法:

Personnel userId = Personnel.JohnDoe;

if (userId.In(Personnel.JohnDoe, Personnel.JaneDoe))
{
    // Do something
}

我不能为此声称功劳，但我也不记得我在哪里看到的.所以，感谢你，匿名的互联网陌生人.

I can't claim credit for this, but I also can't remember where I saw it. So, credit to you, anonymous Internet stranger.

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