在 SO 和 Google 上的 StyleCop 帮助手册中找不到它，所以在这里 ;)

在使用 StyleCop 期间我有一个警告:

SA1121 - UseBuiltInTypeAlias - Readability Rules

The code uses one of the basic C# types, but does not use the built-in alias for the type.

Rather than using the type name or the fully-qualified type name, the built-in aliases for these types should always be used: bool, byte, char, decimal, double, short, int, long, object, sbyte, float, string, ushort, uint, ulong.

所以 String.Empty 是错误的(取决于上述规则)而 string.Empty 是好的。

为什么使用内置别名更好？可以字符串。 Int32、Int64 等在特殊场景下会使代码中的某些内容复杂化？

最佳答案

澄清一下:并不是每个人都同意 StyleCop 的作者。 Win32 和 .NET 大师 Jeffrey Richter 在他的优秀著作中写道 CLR via C# :

The C# language specification states, “As a matter of style, use of the keyword is favored over use of the complete system type name.” I disagree with the language specification; I prefer to use the FCL type names and completely avoid the primitive type names. In fact, I wish that compilers didn’t even offer the primitive type names and forced developers to use the FCL type names instead. Here are my reasons:

• I’ve seen a number of developers confused, not knowing whether to use string or String in their code. Because in C# string (a keyword) maps exactly to System.String (an FCL type), there is no difference and either can be used. Similarly, I’ve heard some developers say that int represents a 32-bit integer when the application is running on a 32-bit OS and that it represents a 64-bit integer when the application is running on a 64-bit OS. This statement is absolutely false: in C#, an int always maps to System.Int32, and therefore it represents a 32-bit integer regardless of the OS the code is running on. If programmers would use Int32 in their code, then this potential confusion is also eliminated.

• In C#, long maps to System.Int64, but in a different programming language, long could map to an Int16 or Int32. In fact, C++/CLI does treat long as an Int32. Someone reading source code in one language could easily misinterpret the code’s intention if he or she were used to programming in a different programming language. In fact, most languages won’t even treat long as a keyword and won’t compile code that uses it.

• The FCL has many methods that have type names as part of their method names. For example, the BinaryReader type offers methods such as ReadBoolean, ReadInt32, ReadSingle, and so on, and the System.Convert type offers methods such as ToBoolean, ToInt32, ToSingle, and so on. Although it’s legal to write the following code, the line with float feels very unnatural to me, and it’s not obvious that the line is correct:

  BinaryReader br = new BinaryReader(...);
  float val = br.ReadSingle(); // OK, but feels unnatural
  Single val = br.ReadSingle(); // OK and feels good
  

• Many programmers that use C# exclusively tend to forget that other programming languages can be used against the CLR, and because of this, C#-isms creep into the class library code. For example, Microsoft’s FCL is almost exclusively written in C# and developers on the FCL team have now introduced methods into the library such as Array’s GetLongLength, which returns an Int64 value that is a long in C# but not in other languages (like C++/CLI). Another example is System.Linq.Enumerable’s LongCount method.

关于C#-StyleCop-SA1121 : UseBuiltInTypeAlias - Readability Rules，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6000517/