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IWMDMDeviceSession::EndSession

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The EndSession method ends a device session.

Syntax

HRESULT EndSession(WMDM_SESSION_TYPEtype,BYTE*pCtx,DWORDdwSizeCtx);

Parameters

type

[in]  A WMDM_SESSION_TYPE describing the type of session to end. This must be the same bitwise OR of the values specified in BeginSession.

pCtx

[in]  Optional pointer to a caller-allocated session context buffer for private communication between the application and the service provider. Applications having knowledge of the underlying service provider can use this buffer to pass context-specific data to it. Windows Media Device Manager does not do anything with this context. The caller is responsible for freeing this buffer.

dwSizeCtx

[in]  Size of the context buffer, in bytes. If the size is 0, pCtx is ignored. If the size is non-zero, pCtx must be a valid pointer

Return Values

The method returns an HRESULT. All the interface methods in Windows Media Device Manager can return any of the following classes of error codes:

  • Standard COM error codes
  • Windows error codes converted to HRESULT values
  • Windows Media Device Manager error codes

For an extenstive list of possible error codes, see Error Codes.

Possible values include, but are not limited to, those in the following table.

Return code Description
S_OK The method succeeded
E_INVALIDARG The session type to end does not match the current session type.
WMDM_E_CALL_OUT_OF_SEQUENCE Attempted to call EndSession before BeginSession.

Remarks

A session brackets a group of operations to a device, allowing Windows Media Device Manager components to optimize performance by performing common setup and shutdown functions only once, rather than with each individual transfer. For details see BeginSession.

In response to an EndSession call, Windows Media Device Manager calls EndSession on the secure content provider and the service provider. If either of them fails the call, Windows Media Device Manager returns an error. In that case, it is possible that EndSession succeeded for one of the components.

Example Code

The following C++ code demonstrates using a session to bundle an Insert3 call on a device. The code loops through a number of files stored in a vector and sends them to the device.

// Get the session interface.
CComQIPtr<IWMDMDeviceSession> pSession(pDevice);
if (pDevice == NULL)
{
    // TODO: Display a message that the app wasn't able to retrieve the IWMDMDeviceSession interface.
    return E_NOINTERFACE;
}

// Start the session. We don't use a custom buffer.
hr = pSession->BeginSession(WMDM_SESSION_TRANSFER_TO_DEVICE, NULL, NULL);
if (hr != S_OK)
{
    / /TODO: Display a message indicating that the session failed to start.
    return hr;
}
else
{
    // TODO: Display a message indicating that the session started.
}


// Insert files. These calls happen synchronously.
UINT flags = WMDM_MODE_BLOCK | WMDM_STORAGECONTROL_INSERTINTO | WMDM_FILE_CREATE_OVERWRITE | WMDM_CONTENT_FILE;
CComPtr<IWMDMStorage> pNewStorage;
for(int i = 0; i < sourceFiles.size(); i++)
{
    hr = pStorageControl3->Insert3(
        flags,
        WMDM_FILE_ATTR_FOLDER,
        sourceFiles[i],
        NULL, // Use default name.
        NULL, // Don't specify IWMDMOperation
        NULL, // Don't specify IWMDMProgress
        NULL, // Don't specify metadata
        NULL, // Nothing to send to the SCP.
        &pNewStorage);

    if (pNewStorage != NULL)
        pNewStorage.Release();
    CHECK_HR(hr, "Sent file " << sourceFiles[i] << " to the device.", "Couldn't send file " << sourceFiles[i] << " to the device");
}

// Close the session.
hr = pSession->EndSession(WMDM_SESSION_TRANSFER_TO_DEVICE, NULL, NULL);
CHECK_HR(hr,"Closed the session.","Couldn't close the session.");

Requirements

Header: Defined in mswmdm.h.

Library: mssachlp.lib

See Also