为什么 COM Interop 将 VB6 布尔值视为 C# Short？
我有一个遗留的 VB6 应用程序，它定义了以下结构：
Public Type DrawDown
Date As Date
Amount As Currency
CapitaliseInterest As Boolean
End Type
使用 tlbimp.exe 生成互操作程序集，但结构最终如下：
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct DrawDown
{
public DateTime Date;
[MarshalAs(UnmanagedType.Currency)]
public decimal Amount;
public short CapitaliseInterest;
}
我正在使用 .NET 4.0。
为什么 VB6 Boolean 被转换为 C# short 而不是 bool？
I have a legacy VB6 application that has the following structure defined:
Public Type DrawDown
Date As Date
Amount As Currency
CapitaliseInterest As Boolean
End Type
An interop assembly is generated using tlbimp.exe but the structure ends up as the following:
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct DrawDown
{
public DateTime Date;
[MarshalAs(UnmanagedType.Currency)]
public decimal Amount;
public short CapitaliseInterest;
}
I'm using .NET 4.0.
Why does the VB6 Boolean get translated to a C# short instead of a bool?
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VB6 使用 VARIANT_BOOL 类型，
请在此处查找有关它的信息和历史记录： BOOL 与 VARIANT_BOOL 与 BOOLEAN 与 boo
VB6 uses the VARIANT_BOOL type,
find info and history about it here: BOOL vs. VARIANT_BOOL vs. BOOLEAN vs. boo
因为它是一个。
VB6 布尔值是 16 位值，其中 0 为假，任何非零为真，但设置为 true 的内容会设置为 -1 (0xFFFF)。这样，许多布尔值与数字的组合都可以在 VB6 中很好地工作，因为
x AND TRUE给出x，x OR FALSE给出x、x AND FALSE给出FALSE等等，按位运算符和布尔运算符的逻辑相同。不幸的是，这也意味着4 AND 2是假的，尽管它是TrueThing AND OtherTrueThing，因此谨慎的 VB6 程序员并没有过度依赖于此，而是使用了CBool强制该值为 0 或 -1。一般来说，我们可以选择使用自然机器大小来提高机器处理速度，而不是使用单个字节，因为它是最小的可寻址单元，因此具有大小优势。当 16 位机器上的自然大小是（当然是 16 位）时，与现在 32 位和 64 位机器相比，平衡更倾向于自然大小。 Visual Basic 1.0 在 DOS 和 Windows 3.0 上运行，Windows 3.0 可以在 Intel 80286 16 位处理器上运行，所以这并不是一个奇怪的选择。
在 COM 世界中，我们有 VARIANT_BOOL，这只是“布尔值，按照 VB6 的方式完成”的另一种说法，以允许跨语言兼容。 C# 中最接近的东西是
short或ushort，如果我们只关心 C#，我们可以选择其中之一。首先，我们倾向于使用有符号的值而不是无符号的值，这会让我们倾向于short，但ushort也不是符合 CLS 的类型，而且几乎没有任何意义在获得与 COM 的兼容性时引入了与其他 .NET 语言的不兼容性！因此，short是明智的选择。Because it is one.
VB6 bools are 16-bit values where 0 is false and any non-zero is true, but something set to true is set to -1 (0xFFFF). This way a lot of combinations of bools with numbers works well with VB6 because
x AND TRUEgivesx,x OR FALSEgivesx,x AND FALSEgivesFALSEand so on, with the same logic for bit-wise and boolean operators. Unfortunately it also means that4 AND 2is false despite that beingTrueThing AND OtherTrueThing, so cautious VB6 coders didn't over-rely upon this, but usedCBoolto force the value to be either 0 or -1.In general we have the choice of using natural machine size for the machine-processing speed versus using a single byte as it's the smallest addressable unit and hence gives a size advantage. Back when the natural-size on 16-bit machines was, well 16-bits of course, the balance went more in favour of going for the natural size than today when we've 32-bit and 64-bit machines. Visual Basic 1.0 ran on DOS and Windows 3.0 which could run on Intel 80286 16-bit processors, so it's not that strange a choice.
In the COM world, we have VARIANT_BOOL, which is just another way of saying "a bool, done the way VB6 does them", to allow for compatibility across langauges. The closest thing in C# would be either
shortorushort, and if we cared only about C# we could pick either. Firstly though, we tend to use signed more than unsigned values, which would lean us towardshort, but alsoushortis not a CLS-compliant type, and there's hardly any point introducing an incompatibility with other .NET languages in obtaining compatibility with COM! Henceshortis the clear choice.布尔值本质上是一个短整数：
生成互操作程序集可以解决此问题。
有关此内容的文档，请参阅 MSDN。
The
Boolean, under the hood, is essentially a short integer:Generating the interop assembly resolves this.
Documentation per MSDN on this.
您可以将 /VariantBoolFieldToBool 标志传递给 tlbimp.exe，使其生成 C# bool 成员而不是短整型。
请参阅 tlbimp.exe 的官方文档
You can pass the /VariantBoolFieldToBool flag to tlbimp.exe to make it generate a C# bool member instead of the short.
See the official documentation for tlbimp.exe