VT_VARIANT / VT_VECTOR型PROPVARIANT结构的初始化

Question

我很好奇如何初始化VT_VARIANT \ VT_VECTOR类型的PROPVARIANT结构。我知道的一个现有模型是HeadingPairs属性集的DocumentSummaryInformation属性：

HeadingPairs属性以重复对VT_LPSTR (或VT_LPWSTR)和VT_I4值的形式存储为变体向量。

我知道各种Init函数，例如创建一个InitPropVariantFromStringAsVector _ VT_VECTOR _

如有任何帮助或建议，将不胜感激。

谢谢。

Answer 1

没有现成的Win32函数来用PROPVARIANT值的向量初始化PROPVARIANT，这是正确的。您只需手动初始化它，即分配一个PROPVARIANT数组，然后将指向该数组的指针分配给PROPVARIANT::capropvar.pElems字段，将数组的长度分配给PROPVARIANT::capropvar.cElems字段，例如：

int count = ...;
PROPVARIANT *arr = (PROPVARIANT*) CoTaskMemAlloc(count * sizeof(PROPVARIANT));

// initialize array values as needed...

PROPVARIANT pv;
PropVariantInit(&pv);
      
pv.vt = VT_VECTOR | VT_VARIANT;
pv.capropvar.pElems = arr;
pv.capropvar.cElems = count;

// use pv as needed...

PropVariantClear(&pv);

Answer 2

下面是一个基于雷米用解决方案编写的AutoHotkey的原型：

VariantVector := [{vt:0x001F, val:"hello world"}, {vt:0x0003, val:3}]
VarSetCapacity(PropVariant, 8 + 2 * A_PtrSize, 0)
InitPropVariatFromVariantAsVector(PropVariant, VariantVector)
; Do something here...
PropVariantClear(PropVariant)
return

InitPropVariatFromVariantAsVector(ByRef PropVariant, VariantVector) {
   static VT_VARIANT := 0x000C
   static VT_VECTOR  := 0x1000
   static Size := 8 + 2 * A_PtrSize
   
   NumPut(VT_VARIANT | VT_VECTOR,  PropVariant, 0, "UShort")
   NumPut(VariantVector.Count(), PropVariant, 8, "UInt")
   ptr := DllCall("Ole32\CoTaskMemAlloc", "UPtr", Size * VariantVector.Count(), "Ptr")
   NumPut(ptr, PropVariant, 8 + A_PtrSize, "Ptr")
   
   for Each, Variant in VariantVector {
      Offset := Size * (Each - 1)
      NumPut(Variant.vt,  ptr + 0, Offset, "UShort")
      Switch Variant.vt
      {
         Case 0x0003: NumPut(Variant.val, ptr + 0, Offset + 8, "Int")  ; VT_I4
         Case 0x001E: DllCall("Shlwapi\SHStrDup", "AStr", Variant.val, "Ptr", ptr + Offset + 8, "Int")  ; VT_LPSTR
         Case 0x001F: DllCall("Shlwapi\SHStrDup", "WStr", Variant.val, "Ptr", ptr + Offset + 8, "Int")  ; VT_LPWSTR
         Default: throw Exception(A_ThisFunc ": Unsupported Variant Type.", -1, Format("0x{:04X}", Variant.vt))
      }
   }
}

PropVariantClear(ByRef PropVariant) {
   return DllCall("Ole32\PropVariantClear", "Ptr", &PropVariant, "Int")
}