移動裝置上的內容
WPD 應用程式完成的另一個常見作業是將內容從裝置上的某個位置傳輸到另一個位置。
使用下表所述的介面來完成內容移動作業。
| 介面 | 描述 |
|---|---|
| IPortableDeviceContent 介面 | 提供存取與內容相關的方法。 |
| IPortableDevicePropVariantCollection 介面 | 提供特定屬性方法的存取權限。 |
範例應用程式ContentTransfer.cpp模組中的MoveContentAlreadyOnDevice函式示範應用程式如何將內容從某個位置移至另一個位置。
MoveContentAlreadyOnDevice 函式完成的第一項工作是查詢設備驅動器，以查看它是否支持內容移動。 這是藉由呼叫 SupportsCommand 協助程式函式並傳遞WPD_COMMAND_OBJECT_MANAGEMENT_MOVE_OBJECTS作為第二個自變數來完成。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszDestinationFolderObjectID[81] = {0};
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDevicePropVariantCollection> pObjectsToMove;
CComPtr<IPortableDevicePropVariantCollection> pObjectsFailedToMove;
if (SupportsCommand(pDevice, WPD_COMMAND_OBJECT_MANAGEMENT_MOVE_OBJECTS) == FALSE)
{
printf("! This device does not support the move operation (i.e. The WPD_COMMAND_OBJECT_MANAGEMENT_MOVE_OBJECTS command)\n");
return;
}
下一個步驟需要提示使用者輸入兩個物件標識碼。 第一個是將移動之內容的標識碼。 第二個是應用程式應該移動此內容之位置的標識碼。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszDestinationFolderObjectID[81] = {0};
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDevicePropVariantCollection> pObjectsToMove;
CComPtr<IPortableDevicePropVariantCollection> pObjectsFailedToMove;
printf("Enter the identifer of the object you wish to move.\n>");
hr = StringCbGetsW(wszSelection,sizeof(wszSelection));
if (FAILED(hr))
{
printf("An invalid object identifier was specified, aborting content moving\n");
}
// Prompt user to enter an object identifier on the device to move.
printf("Enter the identifer of the object you wish to move '%ws' to.\n>", wszSelection);
hr = StringCbGetsW(wszDestinationFolderObjectID,sizeof(wszDestinationFolderObjectID));
if (FAILED(hr))
{
printf("An invalid object identifier was specified, aborting content moving\n");
}
接下來，此範例將擷取一個 IPortableDeviceContent 物件，用於存取 IPortableDeviceContent::Move 方法。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszDestinationFolderObjectID[81] = {0};
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDevicePropVariantCollection> pObjectsToMove;
CComPtr<IPortableDevicePropVariantCollection> pObjectsFailedToMove;
if (SUCCEEDED(hr))
{
hr = pDevice->Content(&pContent);
if (FAILED(hr))
{
printf("! Failed to get IPortableDeviceContent from IPortableDevice, hr = 0x%lx\n",hr);
}
}
最後，內容會移動。 此程式牽涉到下列各項：
- 建立 IPortableDevicePropVariantCollection 物件，以接收要移動的物件之 PROPVARIANT 結構。
- 將 PROPVARIANT 新增至 IPortableDevicePropVariantCollection 物件。
- 叫用 IPortableDeviceContent：：Move 方法。
HRESULT hr = S_OK;
WCHAR wszSelection[81] = {0};
WCHAR wszDestinationFolderObjectID[81] = {0};
CComPtr<IPortableDeviceContent> pContent;
CComPtr<IPortableDevicePropVariantCollection> pObjectsToMove;
CComPtr<IPortableDevicePropVariantCollection> pObjectsFailedToMove;
if (SUCCEEDED(hr))
{
hr = CoCreateInstance(CLSID_PortableDevicePropVariantCollection,
NULL,
CLSCTX_INPROC_SERVER,
IID_IPortableDevicePropVariantCollection,
(VOID**) &pObjectsToMove);
if (SUCCEEDED(hr))
{
if (pObjectsToMove != NULL)
{
PROPVARIANT pv = {0};
PropVariantInit(&pv);
// Initialize a PROPVARIANT structure with the object identifier string
// that the user selected above. Notice we are allocating memory for the
// LPWSTR value. This memory will be freed when PropVariantClear() is
// called below.
pv.vt = VT_LPWSTR;
pv.pwszVal = AtlAllocTaskWideString(wszSelection);
if (pv.pwszVal != NULL)
{
// Add the object identifier to the objects-to-move list
// (We are only moving 1 in this example)
hr = pObjectsToMove->Add(&pv);
if (SUCCEEDED(hr))
{
// Attempt to move the object on the device
hr = pContent->Move(pObjectsToMove, // Object(s) to move
wszDestinationFolderObjectID, // Folder to move to
NULL); // Object(s) that failed to delete (we are only moving 1, so we can pass NULL here)
if (SUCCEEDED(hr))
{
// An S_OK return lets the caller know that the deletion was successful
if (hr == S_OK)
{
printf("The object '%ws' was moved on the device.\n", wszSelection);
}
// An S_FALSE return lets the caller know that the move failed.
// The caller should check the returned IPortableDevicePropVariantCollection
// for a list of object identifiers that failed to be moved.
else
{
printf("The object '%ws' failed to be moved on the device.\n", wszSelection);
}
}
else
{
printf("! Failed to move an object on the device, hr = 0x%lx\n",hr);
}
}
else
{
printf("! Failed to move an object on the device because we could no add the object identifier string to the IPortableDevicePropVariantCollection, hr = 0x%lx\n",hr);
}
}
else
{
hr = E_OUTOFMEMORY;
printf("! Failed to move an object on the device because we could no allocate memory for the object identifier string, hr = 0x%lx\n",hr);
}
// Free any allocated values in the PROPVARIANT before exiting
PropVariantClear(&pv);
}
else
{
printf("! Failed to move an object from the device because we were returned a NULL IPortableDevicePropVariantCollection interface pointer, hr = 0x%lx\n",hr);
}
}
else
{
printf("! Failed to CoCreateInstance CLSID_PortableDevicePropVariantCollection, hr = 0x%lx\n",hr);
}
}
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