IWMSDataSourcePlugin.OpenDataContainer (Visual Basic .NET)

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IWMSDataSourcePlugin.OpenDataContainer (Visual Basic .NET)

The server calls the OpenDataContainer method to open or create a data container.

Syntax

Parameters

pCommandContext

IWMSCommandContext object that specifies the request command context.

pUserContext

IWMSContext object that specifies the user context.

pPresentationContext

IWMSContext object that specifies the presentation context.

pszContainerName

String containing the name of the container to be opened.

dwFlags

UInt32 containing a member of the WMS_DATA_CONTAINER_OPEN_FLAGS enumeration type that indicates the type of access requested. This must be a bitwise OR of one or more of the following values.

Values Description
WMS_DATA_CONTAINER_READ_ACCESS The server requested read access.
WMS_DATA_CONTAINER_WRITE_ACCESS The server requested write access.
WMS_DATA_CONTAINER_CREATE_NEW_CONTAINER The server requested that a new data container be created.
WMS_DATA_CONTAINER_ALLOW_BUFFER_IO The buffered data does not need to be page-aligned.
WMS_DATA_CONTAINER_SHARED_SOURCE The server requested that the data container be used for a shared resource such as a broadcast. If the plug-in determines that the data path must not be shared, it can return COMADMIN_E_PRIVATE_ACCESSDENIED when it calls IWMSDataSourcePluginCallback.OnOpenDataContainer.

pBufferAllocator

IWMSBufferAllocator object that can be used by the data source plug-in to allocate additional buffers for reading or writing data.

pCallback

IWMSDataSourcePluginCallback object containing the callback function. The plug-in calls IWMSDataSourcePluginCallback.OnOpenDataContainer to return the results to the server.

qwContext

UInt64 containing a value defined by the server to identify which OpenDataContainer request the plug-in is responding to when it calls IWMSDataSourcePluginCallback.OnOpenDataContainer. The plug-in must pass this value back unaltered.

Return Values

This method does not return a value. To report an error, the plug-in can throw a COMException object to the server. If the plug-in uses the IWMSEventLog object to log error information, it is recommended that it throw NS_E_PLUGIN_ERROR_REPORTED (0xC00D157D). Typically, the server attempts to make plug-in error information available to the server object model, the Windows Event Viewer, and the troubleshooting list in the details pane of the Windows Media Services MMC. However, if the plug-in uses the IWMSEventLog object to send custom error information to the Windows Event Viewer, throwing NS_E_PLUGIN_ERROR_REPORTED stops the server from also logging to the event viewer. For more information about plug-in error information, see Identifying Plug-in Errors.

Remarks

If the server requests that the data container be used for a shared broadcast by sending WMS_DATA_CONTAINER_SHARED_SOURCE in the dwFlags parameter when it calls OpenDataContainer, and the plug-in determines that the source cannot be shared, the plug-in can return COMADMIN_E_PRIVATE_ACCESSDENIED to the server in the hr parameter of IWMSDataSourcePluginCallback.OnOpenDataContainer. The COMADMIN_E_PRIVATE_ACCESSDENIED error is defined in the WinError.h file. A plug-in can decide that a source must not be shared if, for example, a distribution connection requires authentication or the content must be personalized for a specific end user. When the server receives this error, it deletes the shared data path and creates an on-demand (non-shared) data path instead.

Requirements

Reference: Add a reference to Microsoft.WindowsMediaServices.

Namespace: Microsoft.WindowsMediaServices.Interop.

Assembly: Microsoft.WindowsMediaServices.dll.

Library: WMSServerTypeLib.dll.

Platform: Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; and Windows Server 2008.

See Also

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