VBScript ADODB.Stream type mismatch - vbscript

Question

I am writing an HTA application to manage Hyper-V, and I am stuck on the GetVirtualSystemThumbnailImage script. I took the VBScript example from:
https://msdn.microsoft.com/en-us/library/cc160707(v=vs.85).aspx
but that script never actually calls the sub to write the image file. I tried calling the SaveThumbnailImage sub with the arguments being (objOutParams.ImageData), and I get a "Type Mismatch" error on the stream.WriteText line 81. For some reason, the ADODB is rejecting the binary data? I would appreciate any help with this.
option explicit
dim objWMIService
dim managementService
dim fileSystem
const wmiStarted = 4096
const wmiSuccessful = 0
Main()
'-----------------------------------------------------------------
' Main
'-----------------------------------------------------------------
Sub Main()
dim computer, objArgs, strArgs, vmName, vm
set objArgs = WScript.Arguments
if WScript.Arguments.Count = 1 then
computer = Split(objArgs.Unnamed.Item(0),",")(0)
vmName = Split(objArgs.Unnamed.Item(0),",")(1)
else
WScript.Echo "usage: cscript GetVirtualSystemThumbnailImage.vbs hostName,vmName"
WScript.Quit(1)
end if
set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")
set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization\v2")
set managementService = objWMIService.ExecQuery("select * from Msvm_VirtualSystemManagementService").ItemIndex(0)
set vm = GetComputerSystem(vmName)
if StartVm(vm) then
if GetVirtualSystemThumbnailImage(vm) then
WriteLog "Done"
WScript.Quit(0)
End if
end if
WriteLog "GetVirtualSystemThumbnailImage Failed."
WScript.Quit(1)
End Sub
'-----------------------------------------------------------------
' Retrieve Msvm_VirtualComputerSystem from base on its ElementName
'-----------------------------------------------------------------
Function GetComputerSystem(vmElementName)
' On Error Resume Next
dim query
query = Format1("select * from Msvm_ComputerSystem where ElementName = '{0}'", vmElementName)
set GetComputerSystem = objWMIService.ExecQuery(query).ItemIndex(0)
if (Err.Number <> 0) then
WriteLog Format1("Err.Number: {0}", Err.Number)
WriteLog Format1("Err.Description:{0}",Err.Description)
WScript.Quit(1)
end if
End Function
'-----------------------------------------------------------------
' Save the thumbnail
'-----------------------------------------------------------------
Sub SaveThumbnailImage(thumbnailBytes)
dim stream
Const adTypeText = 2
Const adSaveCreateOverWrite = 2
set stream = CreateObject("ADODB.Stream")
stream.Type = adTypeText
stream.Open
Redim text(ubound(thumbnailBytes) \ 2)
Dim i
for i = lbound(thumbnailBytes) to ubound(thumbnailBytes) step 2
text(i\2) = ChrW(thumbnailBytes(i + 1) * &HFF + thumbnailBytes(i))
next
stream.WriteText text
stream.SaveToFile ".\thumbnail.png", adSaveCreateOverWrite
stream.Close
End Sub
'-----------------------------------------------------------------
' Start the virtual machine
'-----------------------------------------------------------------
Function StartVm(computerSystem)
dim objInParam, objOutParams
StartVm = false
if computerSystem.OperationalStatus(0) = 2 then
StartVm = true
Exit Function
end if
set objInParam = computerSystem.Methods_("RequestStateChange").InParameters.SpawnInstance_()
objInParam.RequestedState = 2
set objOutParams = computerSystem.ExecMethod_("RequestStateChange", objInParam)
if objOutParams.ReturnValue = wmiStarted then
if (WMIJobCompleted(objOutParams)) then
StartVm = true
end if
elseif objOutParams.ReturnValue = wmiSuccessful then
StartVm = true
else
WriteLog Format1("StartVM failed with ReturnValue {0}", wmiStatus)
end if
End Function
'-----------------------------------------------------------------
' Print the thumbnail data
'-----------------------------------------------------------------
Sub PrintThumbnailImage(thumbnailBytes)
dim index
dim i
for index = lbound(thumbnailBytes) to ubound(thumbnailBytes)
WriteLog Format2("{0}:{1} ", index, thumbnailBytes(i))
next
End Sub
'-----------------------------------------------------------------
' Define a virtual system
'-----------------------------------------------------------------
Function GetVirtualSystemThumbnailImage(computerSystem)
dim query, objInParam, objOutParams, virtualSystemsetting
GetVirtualSystemThumbnailImage = false
query = Format1("ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_VirtualSystemsettingData", computerSystem.Path_.Path)
set virtualSystemsetting = objWMIService.ExecQuery(query).ItemIndex(0)
set objInParam = managementService.Methods_("GetVirtualSystemThumbnailImage").InParameters.SpawnInstance_()
objInParam.HeightPixels = 150
objInParam.WidthPixels = 100
objInParam.TargetSystem = virtualSystemsetting.Path_.Path
set objOutParams = managementService.ExecMethod_("GetVirtualSystemThumbnailImage", objInParam)
if objOutParams.ReturnValue = wmiStarted then
if (WMIJobCompleted(objOutParams)) then
GetVirtualSystemThumbnailImage = true
end if
elseif objOutParams.ReturnValue = wmiSuccessful then
Dim strData : strData = objOutParams.ImageData
SaveThumbnailImage(strData)
' PrintThumbnailImage(strData)
GetVirtualSystemThumbnailImage = true
else
WriteLog Format1("GetVirtualSystemThumbnailImage failed with ReturnValue {0}", wmiStatus)
end if
End Function
'-----------------------------------------------------------------
' Handle wmi Job object
'-----------------------------------------------------------------
Function WMIJobCompleted(outParam)
dim WMIJob, jobState
set WMIJob = objWMIService.Get(outParam.Job)
WMIJobCompleted = true
jobState = WMIJob.JobState
while jobState = JobRunning or jobState = JobStarting
WriteLog Format1("In progress... {0}% completed.",WMIJob.PercentComplete)
WScript.Sleep(1000)
set WMIJob = objWMIService.Get(outParam.Job)
jobState = WMIJob.JobState
wend
if (jobState <> JobCompleted) then
WriteLog Format1("ErrorCode:{0}", WMIJob.ErrorCode)
WriteLog Format1("ErrorDescription:{0}", WMIJob.ErrorDescription)
WMIJobCompleted = false
end if
End Function
'-----------------------------------------------------------------
' Create the console log files.
'-----------------------------------------------------------------
Sub WriteLog(line)
dim fileStream
set fileStream = fileSystem.OpenTextFile(".\GetVirtualSystemThumbnailImage.log", 8, true)
' WScript.Echo line
fileStream.WriteLine line
fileStream.Close
End Sub
'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format2(myString, arg0, arg1)
Format2 = Format1(myString, arg0)
Format2 = Replace(Format2, "{1}", arg1)
End Function
'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format1(myString, arg0)
Format1 = Replace(myString, "{0}", arg0)
End Function