IWMSPlaylistParser.WritePlaylist (Visual Basic .NET)
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IWMSPlaylistParser.WritePlaylist (Visual Basic .NET)
The WritePlaylist method writes the playlist files.
Syntax
Parameters
pPlaylist
IXMLDOMDocument object specifying the playlist file to write.
pCallback
IWMSPlaylistParserCallback object that is used by the plug-in to report to the server the result of the call to the WritePlaylist method.
qwContext
UInt64 containing a value defined by the server to identify which call to WritePlaylist the plug-in is responding to when it calls IWMSPlaylistParserCallback.OnWritePlaylist. You must pass this value back unaltered when you call OnWritePlaylist.
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
This method is implemented by the plug-in and called by the server. The server calls the IWMSPlaylistParser.WritePlaylist method, if implemented, with a pointer to the result of the ReadPlaylist method call, which is an IXMLDOMDocument object specifying the playlist file that is to be written. This method need only be called if you want the file saved.
Example Code
The following is a sample user-defined playlist which can be written by the WritePlaylist method.
!- DJ_FILE v1.0 -! (this is a required tag) media1.wmv !- This is a comment -! media2.wmv !- Attributes apply to the next media element -! # author=\"My Name\" # description=\"My media file\" # repeatCount=\"5\" media3.wmv
This implementation of the WritePlaylist method will write the user-defined playlist.
Public Sub WritePlaylist( _ ByVal pPlaylist As interop_msxml.IXMLDOMDocument, _ ByVal pCallback As IWMSPlaylistParserCallback, _ ByVal qwContext As System.UInt64) _ Implements IWMSPlaylistParser.WritePlaylist Dim NodeList As IXMLDOMNodeList Dim pBufAlloc As IWMSBufferAllocator Dim pINSSBuffer As INSSBuffer Dim strPls As String Dim strMedia As String Dim pBuf As IntPtr Dim i As Integer Dim j As Integer Dim Enc As Encoder = Encoding.Unicode.GetEncoder() Dim Bytes As Byte() Dim iBytes As Integer Try strPls = "!- DJ_FILE v1.0 -!" & vbCrLf NodeList = pPlaylist.getElementsByTagName("media") For i = 0 To (NodeList.length - 1) For j = 0 To (NodeList(i).attributes.length - 1) If NodeList(i).attributes(j).nodeName = "src" Then strMedia = NodeList(i).attributes(j).nodeValue Else strPls = strPls & "# " & _ NodeList(i).attributes(j).nodeName & _ "=" & Chr(34) & _ NodeList(i).attributes(j).nodeValue & _ Chr(34) & vbCrLf End If Next If Not strMedia = vbNullString Then strPls = strPls & strMedia & vbCrLf End If Next iBytes = Enc.GetByteCount(strPls.ToCharArray(), 0, _ strPls.Length, False) Bytes = Array.CreateInstance(GetType(Byte), iBytes) iBytes = Enc.GetBytes(strPls.ToCharArray(), 0, _ strPls.Length, Bytes, 0, True) pBufAlloc = m_ClassFactory pBufAlloc.AllocateBuffer(Convert.ToUInt32(iBytes), pINSSBuffer) pINSSBuffer.SetLength(Convert.ToUInt32(iBytes)) pINSSBuffer.GetBuffer(pBuf) Marshal.Copy(Bytes, 0, pBuf, iBytes) pCallback.OnWritePlaylist(S_OK, pINSSBuffer, qwContext) Catch e As Exception pCallback.OnWritePlaylist(E_FAIL, pINSSBuffer, qwContext) End Try End Sub
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; Windows Server 2008.
See Also
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