从自定义结构/类型公开通用值 [英] Exposing common values from a custom structure/type

问题描述

我的一个项目的值类型/结构表示视频格式的自定义标识符字符串.在这种情况下，它将包含一个内容类型字符串，但是可以有所不同.

One of my projects has a value type/struct that represents a custom identifier string for a video format. In this case, it's going to contain a content type string, but that can vary.

我使用了一个结构，因此可以在传递时对其进行强类型化，并对初始字符串值进行一些完整性检查.

I've used a struct so it can be strongly type when it's passed around, and perform some sanity checks on the initial string value.

public struct VideoFormat {
    private string contentType;

    public VideoFormat(string contentType) {
        this.contentType = contentType;
    }

    public string ContentType {
        get { return this.contentType; }
    }

    public override string ToString() {
        return this.contentType;
    }

    // various static methods for implicit conversion to/from strings, and comparisons
}

由于存在一些非常常见的格式，因此我将它们公开为具有默认值的静态只读字段.

As there are a few very common formats, I've exposed these as static read only fields with default values.

public static readonly VideoFormat Unknown = new VideoFormat(string.Empty);
public static readonly VideoFormat JPEG = new VideoFormat("image/jpeg");
public static readonly VideoFormat H264 = new VideoFormat("video/h264");

将公共值公开为静态只读字段还是仅获取属性更好?如果我以后要更改该怎么办?我看到整个.Net框架都使用了这两种方法，例如System.Drawing.Color使用静态只读属性，而System.String具有用于String.Empty的静态只读字段，而System.Int32具有用于MinValue的const.

Is it better to expose the common values as static read only fields or as get only properties? what if I want to change them later? I see both methods used throughout the .Net framework, e.g. System.Drawing.Color uses static readonly properties while System.String has a static read only field for String.Empty, and System.Int32 has a const for MinValue.

(大部分复制自此问题，但包含更具体且不直接相关的问题.)

(Mostly copied from this question but with a more specific and not directly related question.)

推荐答案

除非您声明从不更改，否则属性是个好主意.

Properties are a good idea unless you are declaring something that never changes.

使用属性，您可以更改内部实现，而不会影响占用您库的程序并处理更改/变体.使用程序不会中断，也不需要重新编译.

With properties you can change the inside implementation without affecting programs consuming your library and handle changes / variations. Consuming programs wont break and wont require to be recompiled.

例如(我知道这是一个不好的例子，但您明白了.)

e.g. (I know this is a bad example but you get the idea..)

public static VideoFormat H264Format
{
   get{
         // This if statement can be added in the future without breaking other programs.
         if(SupportsNewerFormat)
             return VideoFormat.H265;

         return VideoFormat.H264;
    }
}

还请记住，如果您以后决定将字段更改为属性，则会消耗大量代码.

Also keep in mind that if you decided to change a field to a property in the future, consuming code breaks.

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