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NF:mswmdm.IWMDMOperation.BeginRead |
IWMDMOperation::BeginRead (mswmdm.h) |
The BeginRead method indicates that a "read from device" action is beginning. Windows Media Device Manager only calls this method if the application calls IWMDMStorageControl::Read and passes in this IWMDMOperation interface. |
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wmdm\iwmdmoperation_beginread.htm |
WMDM |
e72caaac-8992-4f11-8020-0455b3d730ad |
12/05/2018 |
BeginRead, BeginRead method [windows Media Device Manager], BeginRead method [windows Media Device Manager],IWMDMOperation interface, IWMDMOperation interface [windows Media Device Manager],BeginRead method, IWMDMOperation.BeginRead, IWMDMOperation::BeginRead, IWMDMOperationBeginRead, mswmdm/IWMDMOperation::BeginRead, wmdm.iwmdmoperation_beginread |
mswmdm.h |
Windows |
Mssachlp.lib |
Windows |
19H1 |
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The BeginRead method indicates that a "read from device" action is beginning. Windows Media Device Manager only calls this method if the application calls IWMDMStorageControl::Read and passes in this IWMDMOperation interface.
The application should return one of the following HRESULT values.
| Return code | Description |
|---|---|
|
The read operation should continue. |
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The read operation should be cancelled without finishing. |
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An unspecified error occurred, and the read operation should be cancelled without finishing. |
This method is called just before the Windows Media Device Manager calls IWMDMOperation::TransferObjectData.
The following C++ code example implements the BeginRead method and outputs a message when a read-from-device action is beginning.
HRESULT BeginRead()
{
// TODO: Display the message: "IWMDMOperation event--BeginRead."
// If the global handle of the source file is uninitialized, fail.
if (m_File == INVALID_HANDLE_VALUE)
return E_FAIL;
// Global status to let TransferObjectData know what kind of
// operation is happening.
m_OperationStatus = OPERATION_READ;
return S_OK;
}