我使用int是为了防止Microsoft将整数的默认实现更改为一些新版本(我们称其为Int32b)。

然后，Microsoft可以将int别名更改为Int32b，我不需要更改任何代码就可以利用他们新的(希望是改进的)整数实现。

这同样适用于任何类型关键字。

根据Visual Studio 2012中的即时窗口，Int32是int型，Int64是long型。输出如下:

sizeof(int)
4
sizeof(Int32)
4
sizeof(Int64)
8
Int32
int
    base {System.ValueType}: System.ValueType
    MaxValue: 2147483647
    MinValue: -2147483648
Int64
long
    base {System.ValueType}: System.ValueType
    MaxValue: 9223372036854775807
    MinValue: -9223372036854775808
int
int
    base {System.ValueType}: System.ValueType
    MaxValue: 2147483647
    MinValue: -2147483648

int和Int32之间没有区别，但由于int是一个语言关键字，许多人在风格上更喜欢它(就像string vs string)。

ECMA-334:2006 c#语言规范(p18)

每个预定义类型都是系统提供类型的简写。例如，关键字int指向结构体System.Int32。就风格而言，使用关键字优于使用完整的系统类型名。

int与System相同。Int32，当编译时，它将在CIL中变成相同的东西。

我们在c#中按照惯例使用int，因为c#希望看起来像C和c++(以及Java)，这就是我们在那里使用的……

顺便说一句，我最终使用的是系统。Int32时声明各种Windows API函数的导入。我不确定这是否是一个定义的约定，但它提醒我，我要去一个外部DLL…

虽然它们(大部分)是相同的(参见下面的一个[错误]差异)，但您绝对应该注意并应该使用Int32。

The name for a 16-bit integer is Int16. For a 64 bit integer it's Int64, and for a 32-bit integer the intuitive choice is: int or Int32? The question of the size of a variable of type Int16, Int32, or Int64 is self-referencing, but the question of the size of a variable of type int is a perfectly valid question and questions, no matter how trivial, are distracting, lead to confusion, waste time, hinder discussion, etc. (the fact this question exists proves the point). Using Int32 promotes that the developer is conscious of their choice of type. How big is an int again? Oh yeah, 32. The likelihood that the size of the type will actually be considered is greater when the size is included in the name. Using Int32 also promotes knowledge of the other choices. When people aren't forced to at least recognize there are alternatives it become far too easy for int to become "THE integer type". The class within the framework intended to interact with 32-bit integers is named Int32. Once again, which is: more intuitive, less confusing, lacks an (unnecessary) translation (not a translation in the system, but in the mind of the developer), etc. int lMax = Int32.MaxValue or Int32 lMax = Int32.MaxValue? int isn't a keyword in all .NET languages. Although there are arguments why it's not likely to ever change, int may not always be an Int32.

缺点是要多输入两个字符和[bug]。

这不会编译

public enum MyEnum : Int32
{
    AEnum = 0
}

但这将:

public enum MyEnum : int
{
    AEnum = 0
}