Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
566 views
in Technique[技术] by (71.8m points)

.net - How to declare a class instance as a constant in C#?

I need to implement this:

static class MyStaticClass
{
    public const TimeSpan theTime = new TimeSpan(13, 0, 0);
    public static bool IsTooLate(DateTime dt)
    {
        return dt.TimeOfDay >= theTime;
    }
}

theTime is a constant (seriously :-), like π is, in my case it'd be pointless to read it from settings, for example. And I'd like it to be initialized once and never changed.

But C# doesn't seem to allow a constant to be initialized by a function (which a constructor is). How to overcome this?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Using readonly instead of const can be initialized and not modified after that. Is that what you're looking for?

Code example:

static class MyStaticClass
{
    static readonly TimeSpan theTime;

    static MyStaticClass()
    {
        theTime = new TimeSpan(13, 0, 0);
    }
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...