如何在 C# 中将类实例声明为常量?

How to declare a class instance as a constant in C#?(如何在 C# 中将类实例声明为常量?)
本文介绍了如何在 C# 中将类实例声明为常量?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我需要实现这个:

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

theTime 是一个常数(说真的:-),就像 π 一样,例如,在我的情况下,从设置中读取它是没有意义的.而且我希望它被初始化一次并且永远不会改变.

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.

但 C# 似乎不允许由函数(即构造函数)初始化常量.如何克服?

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

推荐答案

使用 readonly 代替 const 可以初始化,之后不再修改.这就是你要找的吗?

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

代码示例:

static class MyStaticClass
{
    static readonly TimeSpan theTime;

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

这篇关于如何在 C# 中将类实例声明为常量?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持编程学习网!

本站部分内容来源互联网,如果有图片或者内容侵犯您的权益请联系我们删除!

相关文档推荐

DispatcherQueue null when trying to update Ui property in ViewModel(尝试更新ViewModel中的Ui属性时DispatcherQueue为空)
Drawing over all windows on multiple monitors(在多个监视器上绘制所有窗口)
Programmatically show the desktop(以编程方式显示桌面)
c# Generic Setlt;Tgt; implementation to access objects by type(按类型访问对象的C#泛型集实现)
InvalidOperationException When using Context Injection in ASP.Net Core(在ASP.NET核心中使用上下文注入时发生InvalidOperationException)
LINQ many-to-many relationship, how to write a correct WHERE clause?(LINQ多对多关系,如何写一个正确的WHERE子句?)