Friend Class Program<System.MTAThreadAttribute()>Shared Sub Main(ByVal args() As String) ' Added for clarity, but this line is redundant because MTA is the default.' Create the secondary thread and pass the printing method for ' the constructor's ThreadStart delegate parameter. The BatchXPSPrinter' class is defined below.Dim printingThread As New Thread(AddressOf BatchXPSPrinter.PrintXPS)' Set the thread that will use PrintQueue.AddJob to single threading.printingThread.SetApartmentState(ApartmentState.STA)' Start the printing thread. The method passed to the Thread ' constructor will execute.printingThread.Start()End Sub 'end MainEnd Class 'end Program classPublic Class BatchXPSPrinterPublic Shared Sub PrintXPS()' Create print server and print queue.Dim localPrintServer As New LocalPrintServer()Dim defaultPrintQueue As PrintQueue = LocalPrintServer.GetDefaultPrintQueue()' Prompt user to identify the directory, and then create the directory object.Console.Write("Enter the directory containing the XPS files: ")Dim directoryPath As String = Console.ReadLine()Dim dir As New DirectoryInfo(directoryPath)' If the user mistyped, end the thread and return to the Main thread.If Not dir.Exists ThenConsole.WriteLine("There is no such directory.")Else' If there are no XPS files in the directory, end the thread ' and return to the Main thread.If dir.GetFiles("*.xps").Length = 0 ThenConsole.WriteLine("There are no XPS files in the directory.")ElseConsole.WriteLine(vbLf & "Jobs will now be added to the print queue.")Console.WriteLine("If the queue is not paused and the printer is working, jobs will begin printing.")' Batch process all XPS files in the directory.For Each f As FileInfo In dir.GetFiles("*.xps")Dim nextFile As String = directoryPath & "\" & f.NameConsole.WriteLine("Adding {0} to queue.", nextFile)Try' Print the Xps file while providing XPS validation and progress notifications.Dim xpsPrintJob As PrintSystemJobInfo = defaultPrintQueue.AddJob(f.Name, nextFile, False)Catch e As PrintJobExceptionConsole.WriteLine(vbLf & vbTab & "{0} could not be added to the print queue.", f.Name)If e.InnerException.Message = "File contains corrupted data." ThenConsole.WriteLine(vbTab & "It is not a valid XPS file. Use the isXPS Conformance Tool to debug it.")End IfConsole.WriteLine(vbTab & "Continuing with next XPS file." & vbLf)End TryNext f ' end for each XPS fileEnd If 'end if there are no XPS files in the directoryEnd If 'end if the directory does not existConsole.WriteLine("Press Enter to end program.")Console.ReadLine()End Sub ' end PrintXPS methodEnd Class ' end BatchXPSPrinter class