C＃中a + = 1和a = a + 1的区别

Question

我发现在C＃中a + = 1不等于a = a + 1。

例如，以下代码编译时没有任何错误： byte b = 10; b + = 5;

while while following code has a compilation error： byte b = 10; b = b + 5;

有人可以让我知道为什么吗？

Answer 1

因为b + 5成为一个整数（的Int32）（主要是因为有过载的可能性）

和下面的化合物分配规范规定：

Otherwise, if the selected operator is a predefined operator, if the return type of the selected operator is explicitly convertible to the type of x, and if y is implicitly convertible to the type of x or the operator is a shift operator, then the operation is evaluated as x = (T)(x op y), where T is the type of x, except that x is evaluated only once.

Answer 2

编译器可能是治疗5作为一个Int32在第二个。你需要投它

Answer 3

因为b += 5编译好像它读取b = (byte)(b + 5)。演员负责转换到正确的类型，所以没有错误。