Console.OpenStandardOutput Method ()

 

Acquires the standard output stream.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

<HostProtectionAttribute(SecurityAction.LinkDemand, UI := True)>
Public Shared Function OpenStandardOutput As Stream

Return Value

Type: System.IO.Stream

The standard output stream.

This method can be used to reacquire the standard output stream after it has been changed by the SetOut method.

The following example illustrates the use of the OpenStandardOutput method. It replaces four consecutive space characters in a string with a tab character. To run it, you must supply two command-line arguments. The first is the name of an existing text file to redirect the standard input stream to. The second is the name of a file to redirect the standard output stream to. This file need not exist. If it does, its contents will be overwritten.

Imports System.IO

Public Class InsertTabs
   Private Const tabSize As Integer = 4
   Private Const usageText As String = "Usage: INSERTTABS inputfile.txt outputfile.txt"

   Public Shared Function Main(args() As String) As Integer
      Dim writer As StreamWriter = Nothing

      If args.Length < 2 Then
         Console.WriteLine(usageText)
         Return 1
      End If

      Try
         ' Attempt to open output file.
         writer = New StreamWriter(args(1))
         ' Redirect standard output from the console to the output file.
         Console.SetOut(writer)
         ' Redirect standard input from the console to the input file.
         Console.SetIn(New StreamReader(args(0)))
      Catch e As IOException
         Dim errorWriter As TextWriter = Console.Error
         errorWriter.WriteLine(e.Message)
         errorWriter.WriteLine(usageText)
         Return 1
      End Try

      Dim line As String = Console.ReadLine()
      While line IsNot Nothing
         Dim newLine As String = line.Replace("".PadRight(tabSize, " "c), ControlChars.Tab)
         Console.WriteLine(newLine)
         line = Console.ReadLine()
      End While
      writer.Close()
      ' Recover the standard output stream so that a 
      ' completion message can be displayed.
      Dim standardOutput As New StreamWriter(Console.OpenStandardOutput())
      standardOutput.AutoFlush = True
      Console.SetOut(standardOutput)
      Console.WriteLine("INSERTTABS has completed the processing of {0}.", args(0))
      Return 0
   End Function 
End Class

.NET Framework
Available since 1.1
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