IWMPSubscriptionService2::prepareForSync method (subscriptionservices.h)

项目
4/26/2023

[The feature associated with this page, Windows Media Player SDK, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of Windows Media Player SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Note This section describes functionality designed for use by online stores. Use of this functionality outside the context of an online store is not supported.

The prepareForSync method is implemented by the online store and called by Windows Media Player just before synchronization happens. Use this method to perform tasks related to synchronizing a digital media file to a device.

Syntax

HRESULT prepareForSync(
  [in] BSTR                            bstrFilename,
  [in] BSTR                            bstrDeviceName,
  [in] IWMPSubscriptionServiceCallback *pCB
);

Parameters

[in] bstrFilename

String containing the name of the digital media file being synchronized.

[in] bstrDeviceName

String containing the canonical name of the device.

[in] pCB

Pointer to an IWMPSubscriptionServiceCallback interface. The online store uses this pointer to notify Windows Media Player that preparation for synchronization is complete.

Return value

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return code	Description
S_OK	The method succeeded.

Remarks

The string contained in bstrDeviceName is not the same name retrieved using IWMPSyncDevice::get_deviceName. Rather, it is the canonical name retrieved by using the IWMDMDevice2::GetCanonicalName method provided by the Windows Media Device Manager SDK.

Your code should not perform lengthy operations synchronously when Windows Media Player calls this method. Instead, you must perform time-consuming tasks on a separate worker thread. When the worker thread has completed its work, it must call IWMPSubscriptionServiceCallback::onComplete.

Use the following procedure to provide your worker thread with a pointer to an IWMPSubscriptionServiceCallback interface.

Pass pCB to CoMarshalInterThreadInterfaceInStream, which returns an IStream pointer.
Pass the IStream pointer to your worker thread.
In your worker thread, call CoGetInterfaceAndReleaseStream, which returns an interface pointer that you can use to call onComplete.

When you call IWMPSubscriptionServiceCallback::onComplete, you should return a success code to allow Windows Media Player to continue synchronizing the specified digital media file, or an error code to disallow synchronization. Windows Media Player displays an error message based on the error code you provide. You should avoid using generic HRESULTs, such as E_FAIL. Instead, you can return the HRESULT error code you receive from a call to one of the Windows Media SDKs, such as the Windows Media Device Manager SDK, or one of the error codes in nserror.h, which can be found in the \Include folder where you installed the Windows Media Player SDK.

Requirements

Requirement	Value
Minimum supported client	Windows Media Player 10 or later.
Target Platform	Windows
Header	subscriptionservices.h

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