值类型和原始类型，以及非原始类型和引用类型有什么区别吗？ 如果是，那么彼此之间有何不同

Question

C#: Is there any difference Value Type and Primitive Type, and Non Primitive Type and Reference Type. If yes then how all are different from each other. I read it in C# documentation but it could clear my doubt about primitive and Non Primitive type.

Answer 1

The C# specification, ECMA-334 , does not define the term Primitive Type . It does have the term Simple Type . There is also Type.IsPrimitive in the.Net Library.

The CLR (.Net) specification, ECMA-335 , also doesn't define it, but it does have Built-In Types , however they are not quite the same as simple types from C#.

Weirdly enough, ECMA-335 does specify simple types, but only for custom attribute constructors, and corresponds to Type.IsPrimitive .

Value/reference types are somewhat orthogonal to that.

• Value Type
  This is a CLR (.Net) term, and is the same as a struct in C#. It is passed by value (copy/value semantics).

• Reference Type
  This is also a CLR term, and is the same as class in C#. It is passed by reference.

• Simple Type
  This is a C# term. It only includes struct s, and only the following are simple types:
  sbyte byte short ushort int uint long ulong char float double bool decimal .
  Note that string and object are not in this list, even though they have alias names in C#.

• Type.IsPrimitive
  This is the same list as above, except that it does not include decimal . It is unclear what it is supposed to represent in the specifications.

• Built-in types
  This is a CLR term, and refers to the same list as above, but also includes object , string (both of which are reference types) and TypedReference .