Console.Error Properti
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Mendapatkan aliran output kesalahan standar.
public:
static property System::IO::TextWriter ^ Error { System::IO::TextWriter ^ get(); };public static System.IO.TextWriter Error { get; }static member Error : System.IO.TextWriterPublic Shared ReadOnly Property Error As TextWriterNilai Properti
TextWriter yang mewakili aliran output kesalahan standar.
Contoh
Contoh berikut adalah utilitas baris perintah bernama ExpandTabs yang menggantikan karakter tab dalam file teks dengan empat spasi, nilai yang ditentukan oleh tabSize variabel. Ini mengalihkan aliran input dan output standar ke file, tetapi menggunakan Error properti untuk menulis aliran kesalahan standar ke konsol. Ini dapat diluncurkan dari baris perintah dengan memberikan nama file yang berisi karakter tab dan nama file output.
using System;
using System.IO;
public class ExpandTabs
{
private const int tabSize = 4;
private const string usageText = "Usage: EXPANDTABSEX inputfile.txt outputfile.txt";
public static void Main(string[] args)
{
StreamWriter writer = null;
if (args.Length < 2) {
Console.WriteLine(usageText);
return;
}
try {
writer = new StreamWriter(args[1]);
Console.SetOut(writer);
Console.SetIn(new StreamReader(args[0]));
}
catch(IOException e) {
TextWriter errorWriter = Console.Error;
errorWriter.WriteLine(e.Message);
errorWriter.WriteLine(usageText);
return;
}
int i;
while ((i = Console.Read()) != -1) {
char c = (char)i;
if (c == '\t')
Console.Write(("").PadRight(tabSize, ' '));
else
Console.Write(c);
}
writer.Close();
// Recover the standard output stream so that a
// completion message can be displayed.
StreamWriter standardOutput = new StreamWriter(Console.OpenStandardOutput());
standardOutput.AutoFlush = true;
Console.SetOut(standardOutput);
Console.WriteLine("EXPANDTABSEX has completed the processing of {0}.", args[0]);
return;
}
}
open System
open System.IO
let tabSize = 4
let usageText = "Usage: EXPANDTABSEX inputfile.txt outputfile.txt"
[<EntryPoint>]
let main args =
if args.Length < 2 then
printfn $"{usageText}"
else
try
use writer = new StreamWriter(args[1])
Console.SetOut writer
Console.SetIn(new StreamReader(args[0]))
let mutable i = Console.Read()
while i <> -1 do
let c = char i
if c = '\t' then
Console.WriteLine(("").PadRight(tabSize, ' '))
else
printf $"{c}"
i <- Console.Read()
// Recover the standard output stream so that a
// completion message can be displayed.
use standardOutput = new StreamWriter(Console.OpenStandardOutput())
standardOutput.AutoFlush <- true
Console.SetOut standardOutput
printfn $"EXPANDTABSEX has completed the processing of {args[0]}."
with :? IOException as e ->
let errorWriter = Console.Error
errorWriter.WriteLine e.Message
errorWriter.WriteLine usageText
0
Imports System.IO
Public Class ExpandTabs
Private Const tabSize As Integer = 4
Private Const usageText As String = "Usage: EXPANDTABSEX inputfile.txt outputfile.txt"
Public Shared Sub Main(args() As String)
Dim writer As StreamWriter = Nothing
If args.Length < 2 Then
Console.WriteLine(usageText)
Exit Sub
End If
Try
writer = New StreamWriter(args(1))
Console.SetOut(writer)
Console.SetIn(New StreamReader(args(0)))
Catch e As IOException
Console.Error.WriteLine(e.Message)
Console.Error.WriteLine(usageText)
Exit Sub
End Try
Dim i As Integer = Console.Read()
While i <> -1
Dim c As Char = Convert.ToChar(i)
If c = ControlChars.Tab Then
Console.Write("".PadRight(tabSize, " "c))
Else
Console.Write(c)
End If
i = Console.Read()
End While
writer.Close()
' Reacquire 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("EXPANDTABSEX has completed the processing of {0}.", args(0))
End Sub
End Class
Contoh berikut adalah penampil file teks sederhana yang menampilkan konten satu atau beberapa file teks ke konsol. Jika tidak ada argumen baris perintah, atau jika ada file yang diteruskan sebagai argumen baris perintah tidak ada, contoh memanggil SetError metode untuk mengalihkan informasi kesalahan ke file, memanggil OpenStandardError metode dalam proses memperoleh kembali aliran kesalahan standar, dan menunjukkan bahwa informasi kesalahan ditulis ke file.
using System;
using System.IO;
public class ViewTextFile
{
public static void Main()
{
String[] args = Environment.GetCommandLineArgs();
String errorOutput = "";
// Make sure that there is at least one command line argument.
if (args.Length <= 1)
errorOutput += "You must include a filename on the command line.\n";
for (int ctr = 1; ctr <= args.GetUpperBound(0); ctr++) {
// Check whether the file exists.
if (!File.Exists(args[ctr])) {
errorOutput += String.Format("'{0}' does not exist.\n", args[ctr]);
}
else {
// Display the contents of the file.
StreamReader sr = new StreamReader(args[ctr]);
String contents = sr.ReadToEnd();
sr.Close();
Console.WriteLine("*****Contents of file '{0}':\n\n",
args[ctr]);
Console.WriteLine(contents);
Console.WriteLine("*****\n");
}
}
// Check for error conditions.
if (!String.IsNullOrEmpty(errorOutput)) {
// Write error information to a file.
Console.SetError(new StreamWriter(@".\ViewTextFile.Err.txt"));
Console.Error.WriteLine(errorOutput);
Console.Error.Close();
// Reacquire the standard error stream.
var standardError = new StreamWriter(Console.OpenStandardError());
standardError.AutoFlush = true;
Console.SetError(standardError);
Console.Error.WriteLine("\nError information written to ViewTextFile.Err.txt");
}
}
}
// If the example is compiled and run with the following command line:
// ViewTextFile file1.txt file2.txt
// and neither file1.txt nor file2.txt exist, it displays the
// following output:
// Error information written to ViewTextFile.Err.txt
// and writes the following text to ViewTextFile.Err.txt:
// 'file1.txt' does not exist.
// 'file2.txt' does not exist.
open System
open System.IO
let args = Environment.GetCommandLineArgs()[1..]
let mutable errorOutput = ""
// Make sure that there is at least one command line argument.
if args.Length < 1 then
errorOutput <- errorOutput + "You must include a filename on the command line.\n"
for file in args do
// Check whether the file exists.
if File.Exists file then
errorOutput <- errorOutput + $"'{file}' does not exist.\n"
else
// Display the contents of the file.
use sr = new StreamReader(file)
let contents = sr.ReadToEnd()
Console.WriteLine $"*****Contents of file '{file}':\n\n"
Console.WriteLine contents
Console.WriteLine "*****\n"
// Check for error conditions.
if not (String.IsNullOrEmpty errorOutput) then
// Write error information to a file.
Console.SetError(new StreamWriter(@".\ViewTextFile.Err.txt"))
Console.Error.WriteLine errorOutput
Console.Error.Close()
// Reacquire the standard error stream.
use standardError = new StreamWriter(Console.OpenStandardError())
standardError.AutoFlush <- true
Console.SetError standardError
Console.Error.WriteLine "\nError information written to ViewTextFile.Err.txt"
// If the example is compiled and run with the following command line:
// ViewTextFile file1.txt file2.txt
// and neither file1.txt nor file2.txt exist, it displays the
// following output:
// Error information written to ViewTextFile.Err.txt
// and writes the following text to ViewTextFile.Err.txt:
// 'file1.txt' does not exist.
// 'file2.txt' does not exist.
Imports System.IO
Module ViewTextFile
Public Sub Main()
Dim args() As String = Environment.GetCommandLineArgs()
Dim errorOutput As String = ""
' Make sure that there is at least one command line argument.
If args.Length <= 1 Then
errorOutput += "You must include a filename on the command line." +
vbCrLf
End If
For ctr As Integer = 1 To args.GetUpperBound(0)
' Check whether the file exists.
If Not File.Exists(args(ctr)) Then
errorOutput += String.Format("'{0}' does not exist.{1}",
args(ctr), vbCrLf)
Else
' Display the contents of the file.
Dim sr As New StreamReader(args(ctr))
Dim contents As String = sr.ReadToEnd()
sr.Close()
Console.WriteLine("***** Contents of file '{0}':{1}{1}",
args(ctr), vbCrLf)
Console.WriteLine(contents)
Console.WriteLine("*****{0}", vbCrLf)
End If
Next
' Check for error conditions.
If Not String.IsNullOrEmpty(errorOutput) Then
' Write error information to a file.
Console.SetError(New StreamWriter(".\ViewTextFile.Err.txt"))
Console.Error.WriteLine(errorOutput)
Console.Error.Close()
' Reacquire the standard error stream.
Dim standardError As New StreamWriter(Console.OpenStandardError())
standardError.AutoFlush = True
Console.SetError(standardError)
Console.Error.WriteLine("{0}Error information written to ViewTextFile.Err.txt",
vbCrLf)
End If
End Sub
End Module
' If the example is compiled and run with the following command line:
' ViewTextFile file1.txt file2.txt
' and neither file1.txt nor file2.txt exist, it displays the
' following output:
' Error information written to ViewTextFile.Err.txt
' and writes the following text to ViewTextFile.Err.txt:
' 'file1.txt' does not exist.
' 'file2.txt' does not exist.
Perhatikan bahwa StreamWriter.AutoFlush properti diatur ke true sebelum memerlukan kembali aliran kesalahan. Ini memastikan bahwa output akan segera dikirim ke konsol daripada di-buffer.
Keterangan
Aliran kesalahan standar ini diatur ke konsol secara default. Ini dapat diatur ke aliran lain dengan SetError metode . Setelah aliran kesalahan standar dialihkan, aliran dapat diperoleh kembali dengan memanggil OpenStandardError metode .
Dalam aplikasi konsol yang output informasinya sering dialihkan ke file, aliran kesalahan standar yang tersedia melalui Error properti dapat digunakan untuk menampilkan informasi ke konsol bahkan jika output dialihkan. Contoh berikut menampilkan tabel produk untuk 10 angka pada satu waktu yang dimulai dengan 1. Setelah setiap set 10 angka, Error properti digunakan untuk menanyakan kepada pengguna apakah akan menampilkan set berikutnya. Jika output standar dialihkan ke file, pengguna masih ditanya apakah rutinitas harus menghasilkan serangkaian produk berikutnya.
using System;
public class Example
{
public static void Main()
{
int increment = 0;
bool exitFlag = false;
while (!exitFlag) {
if (Console.IsOutputRedirected)
Console.Error.WriteLine("Generating multiples of numbers from {0} to {1}",
increment + 1, increment + 10);
Console.WriteLine("Generating multiples of numbers from {0} to {1}",
increment + 1, increment + 10);
for (int ctr = increment + 1; ctr <= increment + 10; ctr++) {
Console.Write("Multiples of {0}: ", ctr);
for (int ctr2 = 1; ctr2 <= 10; ctr2++)
Console.Write("{0}{1}", ctr * ctr2, ctr2 == 10 ? "" : ", ");
Console.WriteLine();
}
Console.WriteLine();
increment += 10;
Console.Error.Write("Display multiples of {0} through {1} (y/n)? ",
increment + 1, increment + 10);
Char response = Console.ReadKey(true).KeyChar;
Console.Error.WriteLine(response);
if (!Console.IsOutputRedirected)
Console.CursorTop--;
if (Char.ToUpperInvariant(response) == 'N')
exitFlag = true;
}
}
}
open System
let mutable increment = 0
let mutable exitFlag = false
while not exitFlag do
if Console.IsOutputRedirected then
Console.Error.WriteLine $"Generating multiples of numbers from {increment + 1} to {increment + 10}"
Console.WriteLine $"Generating multiples of numbers from {increment + 1} to {increment + 10}"
for i = increment + 1 to increment + 10 do
Console.Write $"Multiples of {i}: "
for j = 1 to 10 do
Console.Write $"""{i * j}{if j = 10 then "" else ", "}"""
Console.WriteLine()
Console.WriteLine()
increment <- increment + 10
Console.Error.Write $"Display multiples of {increment + 1} through {increment + 10} (y/n)? "
let response = Console.ReadKey(true).KeyChar
Console.Error.WriteLine response
if not Console.IsOutputRedirected then
Console.CursorTop <- Console.CursorTop - 1
if Char.ToUpperInvariant response = 'N' then
exitFlag <- true
Module Example
Public Sub Main()
Dim increment As Integer = 0
Dim exitFlag As Boolean = False
Do While Not exitFlag
If Console.IsOutputRedirected Then
Console.Error.WriteLine("Generating multiples of numbers from {0} to {1}",
increment + 1, increment + 10)
End If
Console.WriteLine("Generating multiples of numbers from {0} to {1}",
increment + 1, increment + 10)
For ctr As Integer = increment + 1 To increment + 10
Console.Write("Multiples of {0}: ", ctr)
For ctr2 As Integer = 1 To 10
Console.Write("{0}{1}", ctr * ctr2, If(ctr2 = 10, "", ", "))
Next
Console.WriteLine()
Next
Console.WriteLine()
increment += 10
Console.Error.Write("Display multiples of {0} through {1} (y/n)? ",
increment + 1, increment + 10)
Dim response As Char = Console.ReadKey(True).KeyChar
Console.Error.WriteLine(response)
If Not Console.IsOutputRedirected Then
Console.CursorTop = Console.CursorTop - 1
End If
If Char.ToUpperInvariant(response) = "N" Then exitFlag = True
Loop
End Sub
End Module
