ファイルの属性を取得する：GetAttributeByIndexEx

GetAttributeByIndexEx を使用してAttributeの数を取得

参考：To Retrieve All Metadata in a File
IWMHeaderInfo3::GetAttributeByIndexEx method
ID3 Tag Support

#include <stdio.h>  //printf　とかで必要
#include <wmsdk.h>  //HRESULT　とかで必要

using namespace System;//Console::ReadLine()で必要

#pragma comment(lib, "wmvcore.lib")   //IWMMetadataEditor　とかで必要

#ifndef GOTO_EXIT_IF_FAILED
#define GOTO_EXIT_IF_FAILED(hr) if(FAILED(hr)) goto Exit;
#endif

#ifndef SAFE_ARRAY_DELETE
#define SAFE_ARRAY_DELETE(x) \
 if(x != NULL) \
{ \
 delete[] x; \
 x = NULL; \
}
#endif

void main(){

 HRESULT hr          = S_OK;

 IWMMetadataEditor * pEditor = NULL;
 IWMHeaderInfo3 * pHeaderInfo = NULL;

 hr = WMCreateEditor(&pEditor);
 hr = pEditor->Open(L"G:\\sampleMovie\\Amanda.wma");
 hr = pEditor->QueryInterface(IID_IWMHeaderInfo, (void**) &pHeaderInfo);

 WORD    cAttributes = 0;
 WCHAR*  pwszName    = NULL;
 WORD    cchName     = 0;
 BYTE*   pbValue     = NULL;
 DWORD   cbValue     = 0;
 WORD    langIndex   = 0;
 WORD    attIndex    = 0;

 WMT_ATTR_DATATYPE attType;

 // Get the total number of attributes in the file.
 //ファイルの属性の総数を取得します。
 hr = pHeaderInfo->GetAttributeCountEx(0xFFFF, &cAttributes);
 GOTO_EXIT_IF_FAILED(hr);

 // Loop through all the attributes, retrieving and displaying each.
 //すべての属性をループし取得表示
 for(attIndex = 0; attIndex < cAttributes; attIndex++)
 {
  //printf("%d 回目\r\n ", attIndex);

  // Get the required buffer lengths for the name and value.
  //名前と値のために必要なバッファ長を取得します。

  hr = pHeaderInfo->GetAttributeByIndexEx(0xFFFF,
   attIndex,
   NULL,
   &cchName,
   NULL,
   NULL,
   NULL,
   &cbValue);

  GOTO_EXIT_IF_FAILED(hr);

  // Allocate the buffers.
  //バッファを割り当てる。属性名
  pwszName = new WCHAR[cchName];

  //WCHAR *pbValue = (WCHAR *) new BYTE[ cbValue ]; 
  //pwszName = (WCHAR *) new BYTE[ cchName ];
  if(pwszName == NULL)
  {
   printf("割り当て失敗\r\n");
   hr = E_OUTOFMEMORY;
   goto Exit;
  }

  ////属性の値
  pbValue = new BYTE[cbValue];
  if(pbValue == NULL)
  {
   printf("割り当て失敗\r\n");
   hr = E_OUTOFMEMORY;
   goto Exit;
  }

  ////属性を取得します。
  hr = pHeaderInfo->GetAttributeByIndexEx(0xFFFF,
   attIndex,
   pwszName,
   &cchName,
   &attType,
   &langIndex,
   pbValue,
   &cbValue);

  GOTO_EXIT_IF_FAILED(hr);

  // Display the attribute global index and name.
  //表示　属性のグローバルインデックスと名前
  printf("%3d - %S (Language %d):\n\t ", attIndex, pwszName, langIndex);

  // Display the attribute depending upon type.
  //　属性のタイプ別に表示
  switch(attType)
  {
  case WMT_TYPE_DWORD:
  case WMT_TYPE_QWORD:
  case WMT_TYPE_WORD:
   printf("%d\n\n", (DWORD) *pbValue);
   break;
  case WMT_TYPE_STRING:
   printf("%S\n\n", (WCHAR*) pbValue);
   break;
  case WMT_TYPE_BINARY:
   printf("<binary value>\n\n");
   break;
  case WMT_TYPE_BOOL:
   printf("%s\n\n", ((BOOL) *pbValue == TRUE) ? "True" : "False");
   break;
  case WMT_TYPE_GUID:
   printf("<GUID value>\n\n", (DWORD) *pbValue);
   break;
  }

  // Release allocated memory for the next pass.
  //次のために、割り当てられたメモリを解放
  SAFE_ARRAY_DELETE(pwszName);
  SAFE_ARRAY_DELETE(pbValue);
  cchName = 0;
  cbValue = 0;

 }// for ループ終了

Exit:
 SAFE_ARRAY_DELETE(pwszName);
 SAFE_ARRAY_DELETE(pbValue);
 Console::ReadLine();//入力待-ウインドウ維持
 return ;
}