將資源新增至物件
除了將物件傳送至裝置之外，也可以將資源新增至物件。 例如，應用程式可以將相片新增至指定連絡人的現有資訊。
系統會使用下表所述的介面來新增資源。
| 介面 | 描述 |
|---|---|
| IPortableDeviceContent 介面 | 提供內容特定方法的存取權。 |
| IPortableDeviceResources 介面 | 將資源屬性和資料寫入裝置時使用。 |
| IPortableDeviceValues 介面 | 用來撰寫描述資源的屬性。 |
| IStream 介面 | 用來簡化將資源寫入裝置。 |
範例應用程式 ContentTransfer.cpp 模組中的 CreateContactPhotoResourceOnDevice 函式示範應用程式如何將相片資源新增至連絡人物件。 此函式會提示使用者輸入裝置上連絡人的物件識別碼，而相片資源將會新增到該裝置上。 然後它會顯示 [檔案][開啟] 對話方塊，讓使用者可以選取要新增的影像。 收集此資料之後，應用程式會將資源寫入裝置。
CreateContactPhotoResourceOnDevice 函式完成的第一項工作是提示使用者輸入要新增相片之連絡人的物件識別碼。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszFilePath[MAX_PATH] = {0};
DWORD cbOptimalTransferSize = 0;
CComPtr<IStream> pFileStream;
CComPtr<IStream> pResourceStream;
CComPtr<IPortableDeviceValues> pResourceAttributes;
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDeviceResources> pResources;
printf("Enter the identifer of the object to which we will add an Audio annotation.\n>");
hr = StringCbGetsW(wszSelection,sizeof(wszSelection));
if (FAILED(hr))
{
printf("An invalid object identifier was specified, aborting resource creation\n");
}do
下一個步驟是擷取 IPortableDeviceContent 物件，然後用來取得 IPortableDeviceResources 物件。 (應用程式會使用此後者的物件來建立和寫入新的 resource.)
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszFilePath[MAX_PATH] = {0};
DWORD cbOptimalTransferSize = 0;
CComPtr<IStream> pFileStream;
CComPtr<IStream> pResourceStream;
CComPtr<IPortableDeviceValues> pResourceAttributes;
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDeviceResources> pResources;
if (SUCCEEDED(hr))
{
hr = pDevice->Content(&pContent);
if (FAILED(hr))
{
printf("! Failed to get IPortableDeviceContent from IPortableDevice, hr = 0x%lx\n",hr);
}
}
if (SUCCEEDED(hr))
{
hr = pContent->Transfer(&pResources);
if (FAILED(hr))
{
printf("! Failed to get IPortableDeviceResources from IPortableDeviceContent, hr = 0x%lx\n",hr);
}
}
在此之後，此範例會顯示 [ 檔案][開啟 ] 對話方塊，可讓使用者指定包含想要新增至連絡人資訊之相片的影像檔名稱。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszFilePath[MAX_PATH] = {0};
DWORD cbOptimalTransferSize = 0;
CComPtr<IStream> pFileStream;
CComPtr<IStream> pResourceStream;
CComPtr<IPortableDeviceValues> pResourceAttributes;
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDeviceResources> pResources;
if (SUCCEEDED(hr))
{
OPENFILENAME OpenFileNameInfo = {0};
OpenFileNameInfo.lStructSize = sizeof(OPENFILENAME);
OpenFileNameInfo.hwndOwner = NULL;
OpenFileNameInfo.lpstrFile = wszFilePath;
OpenFileNameInfo.nMaxFile = ARRAYSIZE(wszFilePath);
OpenFileNameInfo.lpstrFilter = L"JPEG (*.JPG)\0*.JPG\0JPEG (*.JPEG)\0*.JPEG\0JPG (*.JPE)\0*.JPE\0JPG (*.JFIF)\0*.JFIF\0\0";;
OpenFileNameInfo.nFilterIndex = 1;
OpenFileNameInfo.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
OpenFileNameInfo.lpstrDefExt = L"JPG";
if (GetOpenFileName(&OpenFileNameInfo) == FALSE)
{
printf("The transfer operation was cancelled.\n");
hr = E_ABORT;
}
}
一旦範例有 IPortableDeviceResources 物件和映射檔的名稱，它會執行下列動作，以準備實際將資料傳輸到裝置。
- 它會在選取的檔案上開啟 IStream 物件以進行讀取作業。
- 它會建立 IPortableDeviceValues 物件，其中包含影像大小和格式等資訊。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszFilePath[MAX_PATH] = {0};
DWORD cbOptimalTransferSize = 0;
CComPtr<IStream> pFileStream;
CComPtr<IStream> pResourceStream;
CComPtr<IPortableDeviceValues> pResourceAttributes;
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDeviceResources> pResources;
if (SUCCEEDED(hr))
{
// Open the selected file as an IStream. This will simplify reading the
// data and writing to the device.
hr = SHCreateStreamOnFile(wszFilePath, STGM_READ, &pFileStream);
if (SUCCEEDED(hr))
{
// CoCreate the IPortableDeviceValues to hold the resource attributes
hr = CoCreateInstance(CLSID_PortableDeviceValues,
NULL,
CLSCTX_INPROC_SERVER,
IID_IPortableDeviceValues,
(VOID**) &pResourceAttributes);
if (SUCCEEDED(hr))
{
// Fill in the necessary information regarding this resource
// Set the WPD_OBJECT_ID. This informs the driver which object this request is intended for.
hr = pResourceAttributes->SetStringValue(WPD_OBJECT_ID, wszSelection);
if (FAILED(hr))
{
printf("! Failed to set WPD_OBJECT_ID when creating a resource, hr = 0x%lx\n",hr);
}
// Set the WPD_RESOURCE_ATTRIBUTE_RESOURCE_KEY to WPD_RESOURCE_CONTACT_PHOTO
if (SUCCEEDED(hr))
{
hr = pResourceAttributes->SetKeyValue(WPD_RESOURCE_ATTRIBUTE_RESOURCE_KEY, WPD_RESOURCE_CONTACT_PHOTO);
if (FAILED(hr))
{
printf("! Failed to set WPD_RESOURCE_ATTRIBUTE_RESOURCE_KEY to WPD_RESOURCE_CONTACT_PHOTO, hr = 0x%lx\n",hr);
}
}
// Set the WPD_RESOURCE_ATTRIBUTE_TOTAL_SIZE by requesting the total size of the
// data stream.
if (SUCCEEDED(hr))
{
STATSTG statstg = {0};
hr = pFileStream->Stat(&statstg, STATFLAG_NONAME);
if (SUCCEEDED(hr))
{
hr = pResourceAttributes->SetUnsignedLargeIntegerValue(WPD_RESOURCE_ATTRIBUTE_TOTAL_SIZE, statstg.cbSize.QuadPart);
if (FAILED(hr))
{
printf("! Failed to set WPD_RESOURCE_ATTRIBUTE_TOTAL_SIZE, hr = 0x%lx\n",hr);
}
}
else
{
printf("! Failed to get file's total size, hr = 0x%lx\n",hr);
}
}
// Set the WPD_RESOURCE_ATTRIBUTE_FORMAT to WPD_OBJECT_FORMAT_JFIF because we are
// creating a contact photo resource with JPG image data.
if (SUCCEEDED(hr))
{
hr = pResourceAttributes->SetGuidValue(WPD_RESOURCE_ATTRIBUTE_FORMAT, WPD_OBJECT_FORMAT_JFIF);
if (FAILED(hr))
{
printf("! Failed to set WPD_RESOURCE_ATTRIBUTE_FORMAT to WPD_OBJECT_FORMAT_JFIF, hr = 0x%lx\n",hr);
}
}
}
}
if (FAILED(hr))
{
printf("! Failed to open file named (%ws) to transfer to device, hr = 0x%lx\n",wszFilePath, hr);
}
}
準備寫入作業的 IStream 和 IPortableDeviceValues 物件之後，範例會將映射傳送至裝置。 此範例會以三個步驟完成傳輸，如下所示：
- 它會呼叫 IPortableDeviceResources：：CreateResource 方法，在裝置上建立資源。
- 它會呼叫 StreamCopy 協助程式函式，將來來源資料流複製到目的地資料流程。
- 它會呼叫 IPortableDeviceDataStream：：Commit 方法，通知裝置驅動程式傳輸已完成。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszFilePath[MAX_PATH] = {0};
DWORD cbOptimalTransferSize = 0;
CComPtr<IStream> pFileStream;
CComPtr<IStream> pResourceStream;
CComPtr<IPortableDeviceValues> pResourceAttributes;
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDeviceResources> pResources;
if (SUCCEEDED(hr))
{
hr = pResources->CreateResource(pResourceAttributes, // Properties describing this resource
&pResourceStream, // Returned resource data stream (to transfer the data to)
&cbOptimalTransferSize, // Returned optimal buffer size to use during transfer
NULL);
// Since we have IStream-compatible interfaces, call our helper function
// that copies the contents of a source stream into a destination stream.
if (SUCCEEDED(hr))
{
DWORD cbTotalBytesWritten = 0;
hr = StreamCopy(pResourceStream, // Destination (The resource to transfer to)
pFileStream, // Source (The File data to transfer from)
cbOptimalTransferSize, // The driver specified optimal transfer buffer size
&cbTotalBytesWritten); // The total number of bytes transferred from file to the device
if (FAILED(hr))
{
printf("! Failed to transfer object to device, hr = 0x%lx\n",hr);
}
}
else
{
printf("! Failed to get IStream (representing destination object data on the device) from IPortableDeviceContent, hr = 0x%lx\n",hr);
}
// After transferring content to the device, the client is responsible for letting the
// driver know that the transfer is complete by calling the Commit() method
// on the IPortableDeviceDataStream interface.
if (SUCCEEDED(hr))
{
hr = pResourceStream->Commit(0);
if (FAILED(hr))
{
printf("! Failed to commit resource to device, hr = 0x%lx\n",hr);
}
}
}
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