如何在 Visual C# 中定义常量，如 C 中的 #define？
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How to define constants in Visual C# like #define in C?
提问by neuromancer
In C you can define constants like this
在 C 中，您可以像这样定义常量
#define NUMBER 9
so that wherever NUMBER appears in the program it is replaced with 9. But Visual C# doesn't do this. How is it done?
以便程序中出现 NUMBER 的任何地方都替换为 9。但 Visual C# 不这样做。它是如何完成的？
采纳答案by Jimmeh
public const int NUMBER = 9;
You'd need to put it in a class somewhere, and the usage would be ClassName.NUMBER
你需要把它放在某个地方的类中，用法是 ClassName.NUMBER
回答by Vinz
Check How to: Define Constants in C#on MSDN:
在 MSDN 上查看如何：在 C# 中定义常量：
In C# the
#definepreprocessor directive cannot be used to define constants in the way that is typically used in C and C++.
在 C# 中，
#define预处理器指令不能用于以 C 和 C++ 中通常使用的方式定义常量。
回答by Rush
static class Constants
{
public const int MIN_LENGTH = 5;
public const int MIN_WIDTH = 5;
public const int MIN_HEIGHT = 6;
}
// elsewhere
public CBox()
{
length = Constants.MIN_LENGTH;
width = Constants.MIN_WIDTH;
height = Constants.MIN_HEIGHT;
}
回答by Alireza
in c language: #define(e.g. #define counter 100)
在 c 语言中：（#define例如#define counter 100）
in assembly language: equ(e.g. counter equ 100)
汇编语言：equ（例如 counter equ 100）
in c# language: according to msdn refrence:
You use #defineto define a symbol. When you use the symbol as the expression that's passed to the #ifdirective, the expression will evaluate to true, as the following example shows:
在 c# 语言中：根据 msdn 参考：您#define用来定义符号。当您使用符号作为传递给#if指令的表达式时，表达式的计算结果为 true，如以下示例所示：
# define DEBUG
# define DEBUG
The #definedirective cannot be used to declare constant values as is typically done in C and C++. Constants in C# are best defined as static members of a class or struct. If you have several such constants, consider creating a separate "Constants" class to hold them.
该#define指令不能像通常在 C 和 C++ 中那样用于声明常量值。C# 中的常量最好定义为类或结构的静态成员。如果您有多个这样的常量，请考虑创建一个单独的“常量”类来保存它们。
回答by Bobby
In C#, per MSDN library, we have the "const" keyword that does the work of the "#define" keyword in other languages.
在 C# 中，根据 MSDN 库，我们有“const”关键字来完成其他语言中“#define”关键字的工作。
"...when the compiler encounters a constant identifier in C# source code (for example, months), it substitutes the literal value directly into the intermediate language (IL) code that it produces." ( https://msdn.microsoft.com/en-us/library/ms173119.aspx)
“...当编译器在 C# 源代码中遇到常量标识符（例如，months）时，它会将文字值直接替换为它生成的中间语言 (IL) 代码。” ( https://msdn.microsoft.com/en-us/library/ms173119.aspx)
Initialize constants at time of declaration since there is no changing them.
在声明时初始化常量，因为没有更改它们。
public const int cMonths = 12;
回答by Thomas M. Krystyan
What is the "Visual C#"? There is no such thing. Just C#, or .NET C# :)
什么是“Visual C#”？哪有这回事。只是 C# 或 .NET C# :)
Also, Python's convention for constants CONSTANT_NAMEis not very common in C#. We are usually using CamelCaseaccording to MSDN standards, e.g. public const string ExtractedMagicString = "vs2019";
此外，Python 的常量约定CONSTANT_NAME在 C# 中并不常见。我们通常根据 MSDN 标准使用CamelCase，例如public const string ExtractedMagicString = "vs2019";
Source: Defining constants in C#
来源：在 C# 中定义常量
