C＃中a + = 1和a = a + 1的區別

Question

我發現在C＃中a + = 1不等於a = a + 1。

例如，以下代碼編譯時沒有任何錯誤： byte b = 10; b + = 5;

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

有人可以讓我知道爲什麼嗎？

Answer 1

因爲b + 5成爲一個整數（的Int32）（主要是因爲有過載的可能性）

和下面的化合物分配規範規定：

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

編譯器可能是治療5作爲一個Int32在第二個。你需要投它

Answer 3

因爲b += 5編譯好像它讀取b = (byte)(b + 5)。演員負責轉換到正確的類型，所以沒有錯誤。