c# - Marshal.SizeOf(Type t) 函数

Question

我知道 SizeOf() 应该用于与非托管代码交互，但我的问题是为什么 System.Runtime.InteropServices.Marshal.SizeOf(typeof(System. Char)) 返回 1 而不是 2？我假设 C# char 应该等同于大小为 2 个字节的非托管 wchar_t。这会导致问题吗？

Answer 1

来自 Marshal.SizeOf :

For character types, the size is affected by the CharSet value applied to that class.

并根据CharSet Enumeration , 默认为 CharSet.Ansi:

Although the common language runtime default is Auto, languages may override this default. For example, by default C# marks all methods and types as Ansi.

---

例如:

[StructLayout(LayoutKind.Sequential)]
struct A
{
    char c;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
struct B
{
    char c;
}

....

Console.WriteLine("{0} {1}", Marshal.SizeOf(typeof(A)), Marshal.SizeOf(typeof(B)));

输出是

1 2