本文介绍了C＃中readonly和const之间的区别的处理方法，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 29岁程序员，3月因学历无情被辞！ 我从我的应用程序中调用了一个库（dll）的字符串常量值。那么应该使用什么，即readonly或constamt用于库中的常量。有什么区别？ 如果这个问题太天真，请原谅我。 谢谢。I am calling some string constant value of a library (dll) from my application. So what should use i.e. readonly or constamt for those constant in the library. What is the difference?Please forgive me if this question is too naive.Thanks.推荐答案static class NonModifiableDeclarationSet { internal const int SomeInteger = 5; internal const int SomeOtherInteger = SomeInteger * 10; //constant expression // won't compile: //internal const double SomeFloatingPointValue = System.Math.Acos(-1d); // will work: internal static readonly double SomeFloatingPointValue = System.Math.Acos(-1d);} 在此示例中， SomeFloatingPointValue 将在初始化期间初始化运行时间到使用它的时刻，但它在初始化后无法修改，这对于维护和作为一个万无一失的功能非常重要。它也可以在构造函数中初始化。使用 const 无法实现此效果。 请参阅： http://msdn.microsoft.com/en-us/library/acdd6hb7 ％28v = vs.100％29.aspx [ ^ ]。 -SAIn this example, SomeFloatingPointValue will be initialized during run time when by the moment it is used, but it cannot be modified after it it initialized, which important for maintenance and as a fool-proof feature. It can also be initialize in a constructor. This effect could not be achieved with const.Please see:http://msdn.microsoft.com/en-us/library/acdd6hb7%28v=vs.100%29.aspx[^].—SA//Project 1. Main applicationusing System;namespace ConstReadOnlyTest { class Program { static void Main(string[] args) { Console.WriteLine("Value of Constant from Library: {0}", SupportingLib.Class1.ConstString); Console.WriteLine("Value of Read ony variable from Library: {0}",SupportingLib.Class1.ReadOnlyString); Console.ReadKey(); } }}//Project 2. Referenced library, procured from other company say Comapany A.//The version of compile lib is say 1.0.0.0using System;namespace SupportingLib { public class Class1 { public const string ConstString = "Constant"; public static readonly string ReadOnlyString = "Readonly"; }} 当我编译此代码并运行它时输出为When I compile this code and run it the output isValue of Constant from Library: ConstantValue of Read ony variable from Library: Readonly 我的应用程序已发货。之后，在引用的库中进行了更改 和A公司为我提供了相同版本1.0.0.0的新编译库 这是引用库中已更改的代码My application is shipped. Later, a change is made in the referenced libraryand Company A supplied me new compiled library with same version 1.0.0.0This is the changed code in the referenced librarypublic const string ConstString = "Constant Changed";public static readonly string ReadOnlyString = "Readonly Changed"; 如果不重新编译我的应用程序，我只向用户提供了引用库的新编译版本。然后输出是Without recompiling my application I have only supplied the new compiled version of the referenced library to the user. Then the output isValue of Constant from Library: ConstantValue of Read ony variable from Library: Readonly Changed 我编译应用程序的原因是从引用的程序集中复制了字符串Constant，并将其放在我的可执行代码中。然而，对于只读变量，程序在运行时从引用的程序集读取。 因此，当我提供新的编译库时，程序确实从中读取了只读变量新编译的引用库。因此，在第二行输出中，我们得到了：Readonly Changed 而程序在我的应用程序中使用常量，因此在第一行打印Constant值。 希望我澄清了我的想法。The reason being when I compiled my application the string "Constant" was copied from the referenced assembly and placed in my executable code. Whereas, for Read only variable the program reads from the referenced assembly at run time.So, when I supplied new compiled library the program did read the read only variable from the new compiled referenced library. Hence in the second line of output we got: "Readonly Changed"Whereas the program used the constant from within my application so the value "Constant" is printed in the first line.Hope I clarified what I thought. 这篇关于C＃中readonly和const之间的区别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！ 上岸，阿里云！
