Process.BeginErrorReadLine Yöntem
Tanım
Önemli
Bazı bilgiler ürünün ön sürümüyle ilgilidir ve sürüm öncesinde önemli değişiklikler yapılmış olabilir. Burada verilen bilgilerle ilgili olarak Microsoft açık veya zımni hiçbir garanti vermez.
Uygulamanın yeniden yönlendirilen StandardError akışında zaman uyumsuz okuma işlemlerini başlatır.
public:
void BeginErrorReadLine();public void BeginErrorReadLine();[System.Runtime.InteropServices.ComVisible(false)]
public void BeginErrorReadLine();member this.BeginErrorReadLine : unit -> unit[<System.Runtime.InteropServices.ComVisible(false)>]
member this.BeginErrorReadLine : unit -> unitPublic Sub BeginErrorReadLine ()- Öznitelikler
Özel durumlar
RedirectStandardError özelliği false.
-veya-
Akışta StandardError zaman uyumsuz bir okuma işlemi zaten devam ediyor.
-veya-
Akış StandardError , zaman uyumlu bir okuma işlemi tarafından kullanılmıştır.
Örnekler
Aşağıdaki örnek, uzak bilgisayardaki kullanılabilir ağ kaynaklarını listelemek için komutunu kullanır net view . Kullanıcı, hedef bilgisayar adını komut satırı bağımsız değişkeni olarak sağlar. Kullanıcı hata çıkışı için bir dosya adı da sağlayabilir. Örnek, net komutunun çıkışını toplar, işlemin tamamlanmasını bekler ve ardından çıkış sonuçlarını konsola yazar. Kullanıcı isteğe bağlı hata dosyasını sağlarsa, örnek dosyaya hatalar yazar.
// Define the namespaces used by this sample.
using System;
using System.Text;
using System.Globalization;
using System.IO;
using System.Diagnostics;
using System.Threading;
using System.ComponentModel;
namespace ProcessAsyncStreamSamples
{
class ProcessNetStreamRedirection
{
// Define static variables shared by class methods.
private static StreamWriter streamError =null;
private static String netErrorFile = "";
private static StringBuilder netOutput = null;
private static bool errorRedirect = false;
private static bool errorsWritten = false;
public static void RedirectNetCommandStreams()
{
String netArguments;
Process netProcess;
// Get the input computer name.
Console.WriteLine("Enter the computer name for the net view command:");
netArguments = Console.ReadLine().ToUpper(CultureInfo.InvariantCulture);
if (String.IsNullOrEmpty(netArguments))
{
// Default to the help command if there is not an input argument.
netArguments = "/?";
}
// Check if errors should be redirected to a file.
errorsWritten = false;
Console.WriteLine("Enter a fully qualified path to an error log file");
Console.WriteLine(" or just press Enter to write errors to console:");
netErrorFile = Console.ReadLine().ToUpper(CultureInfo.InvariantCulture);
if (!String.IsNullOrEmpty(netErrorFile))
{
errorRedirect = true;
}
// Note that at this point, netArguments and netErrorFile
// are set with user input. If the user did not specify
// an error file, then errorRedirect is set to false.
// Initialize the process and its StartInfo properties.
netProcess = new Process();
netProcess.StartInfo.FileName = "Net.exe";
// Build the net command argument list.
netProcess.StartInfo.Arguments = String.Format("view {0}",
netArguments);
// Set UseShellExecute to false for redirection.
netProcess.StartInfo.UseShellExecute = false;
// Redirect the standard output of the net command.
// This stream is read asynchronously using an event handler.
netProcess.StartInfo.RedirectStandardOutput = true;
netProcess.OutputDataReceived += new DataReceivedEventHandler(NetOutputDataHandler);
netOutput = new StringBuilder();
if (errorRedirect)
{
// Redirect the error output of the net command.
netProcess.StartInfo.RedirectStandardError = true;
netProcess.ErrorDataReceived += new DataReceivedEventHandler(NetErrorDataHandler);
}
else
{
// Do not redirect the error output.
netProcess.StartInfo.RedirectStandardError = false;
}
Console.WriteLine("\nStarting process: net {0}",
netProcess.StartInfo.Arguments);
if (errorRedirect)
{
Console.WriteLine("Errors will be written to the file {0}",
netErrorFile);
}
// Start the process.
netProcess.Start();
// Start the asynchronous read of the standard output stream.
netProcess.BeginOutputReadLine();
if (errorRedirect)
{
// Start the asynchronous read of the standard
// error stream.
netProcess.BeginErrorReadLine();
}
// Let the net command run, collecting the output.
netProcess.WaitForExit();
if (streamError != null)
{
// Close the error file.
streamError.Close();
}
else
{
// Set errorsWritten to false if the stream is not
// open. Either there are no errors, or the error
// file could not be opened.
errorsWritten = false;
}
if (netOutput.Length > 0)
{
// If the process wrote more than just
// white space, write the output to the console.
Console.WriteLine("\nPublic network shares from net view:\n{0}\n",
netOutput);
}
if (errorsWritten)
{
// Signal that the error file had something
// written to it.
String [] errorOutput = File.ReadAllLines(netErrorFile);
if (errorOutput.Length > 0)
{
Console.WriteLine("\nThe following error output was appended to {0}.",
netErrorFile);
foreach (String errLine in errorOutput)
{
Console.WriteLine(" {0}", errLine);
}
}
Console.WriteLine();
}
netProcess.Close();
}
private static void NetOutputDataHandler(object sendingProcess,
DataReceivedEventArgs outLine)
{
// Collect the net view command output.
if (!String.IsNullOrEmpty(outLine.Data))
{
// Add the text to the collected output.
netOutput.Append(Environment.NewLine + " " + outLine.Data);
}
}
private static void NetErrorDataHandler(object sendingProcess,
DataReceivedEventArgs errLine)
{
// Write the error text to the file if there is something
// to write and an error file has been specified.
if (!String.IsNullOrEmpty(errLine.Data))
{
if (!errorsWritten)
{
if (streamError == null)
{
// Open the file.
try
{
streamError = new StreamWriter(netErrorFile, true);
}
catch (Exception e)
{
Console.WriteLine("Could not open error file!");
Console.WriteLine(e.Message.ToString());
}
}
if (streamError != null)
{
// Write a header to the file if this is the first
// call to the error output handler.
streamError.WriteLine();
streamError.WriteLine(DateTime.Now.ToString());
streamError.WriteLine("Net View error output:");
}
errorsWritten = true;
}
if (streamError != null)
{
// Write redirected errors to the file.
streamError.WriteLine(errLine.Data);
streamError.Flush();
}
}
}
}
}
// Define the namespaces used by this sample.
open System
open System.Text
open System.Globalization
open System.IO
open System.Diagnostics
// Define variables shared by functions.
let mutable streamError = Unchecked.defaultof<StreamWriter>
let mutable netErrorFile = ""
let mutable netOutput = StringBuilder()
let mutable errorRedirect = false
let mutable errorsWritten = false
let netOutputDataHandler (sendingProcess: obj) (outLine: DataReceivedEventArgs) =
// Collect the net view command output.
if String.IsNullOrEmpty outLine.Data |> not then
// Add the text to the collected output.
netOutput.Append(Environment.NewLine + " " + outLine.Data) |> ignore
let netErrorDataHandler (sendingProcess: obj) (errLine: DataReceivedEventArgs) =
// Write the error text to the file if there is something
// to write and an error file has been specified.
if String.IsNullOrEmpty errLine.Data |> not then
if not errorsWritten then
if isNull streamError then
// Open the file.
try
streamError <- new StreamWriter(netErrorFile, true)
with e ->
printfn "Could not open error file!"
printfn $"{e.Message}"
if isNull streamError |> not then
// Write a header to the file if this is the first
// call to the error output handler.
streamError.WriteLine()
streamError.WriteLine DateTime.Now
streamError.WriteLine "Net View error output:"
errorsWritten <- true
if isNull streamError |> not then
// Write redirected errors to the file.
streamError.WriteLine errLine.Data
streamError.Flush()
let redirectNetCommandStreams () =
// Get the input computer name.
printfn "Enter the computer name for the net view command:"
let netArguments = stdin.ReadLine().ToUpper CultureInfo.InvariantCulture
// Default to the help command if there is not an input argument.
let netArguments =
if String.IsNullOrEmpty netArguments then
"/?"
else
netArguments
// Check if errors should be redirected to a file.
errorsWritten <- false
printfn "Enter a fully qualified path to an error log file"
printfn " or just press Enter to write errors to console:"
netErrorFile <- stdin.ReadLine().ToUpper CultureInfo.InvariantCulture
if String.IsNullOrEmpty netErrorFile |> not then
errorRedirect <- true
// Note that at this point, netArguments and netErrorFile
// are set with user input. If the user did not specify
// an error file, then errorRedirect is set to false.
// Initialize the process and its StartInfo properties.
let netProcess = new Process()
netProcess.StartInfo.FileName <- "Net.exe"
// Build the net command argument list.
netProcess.StartInfo.Arguments <- $"view {netArguments}"
// Set UseShellExecute to false for redirection.
netProcess.StartInfo.UseShellExecute <- false
// Redirect the standard output of the net command.
// This stream is read asynchronously using an event handler.
netProcess.StartInfo.RedirectStandardOutput <- true
netProcess.OutputDataReceived.AddHandler(DataReceivedEventHandler netOutputDataHandler)
netOutput <- new StringBuilder()
if errorRedirect then
// Redirect the error output of the net command.
netProcess.StartInfo.RedirectStandardError <- true
netProcess.ErrorDataReceived.AddHandler(DataReceivedEventHandler netErrorDataHandler)
else
// Do not redirect the error output.
netProcess.StartInfo.RedirectStandardError <- false
printfn $"\nStarting process: net {netProcess.StartInfo.Arguments}"
if errorRedirect then
printfn $"Errors will be written to the file {netErrorFile}"
// Start the process.
netProcess.Start() |> ignore
// Start the asynchronous read of the standard output stream.
netProcess.BeginOutputReadLine()
if errorRedirect then
// Start the asynchronous read of the standard error stream.
netProcess.BeginErrorReadLine()
// Let the net command run, collecting the output.
netProcess.WaitForExit()
if streamError <> null then
// Close the error file.
streamError.Close()
else
// Set errorsWritten to false if the stream is not
// open. Either there are no errors, or the error
// file could not be opened.
errorsWritten <- false
if netOutput.Length > 0 then
// If the process wrote more than just
// white space, write the output to the console.
printfn $"\nPublic network shares from net view:\n{netOutput}\n"
if errorsWritten then
// Signal that the error file had something
// written to it.
let errorOutput = File.ReadAllLines netErrorFile
if errorOutput.Length > 0 then
printfn $"\nThe following error output was appended to {netErrorFile}."
for errLine in errorOutput do
printfn $" {errLine}"
printfn ""
netProcess.Close()
' Define the namespaces used by this sample.
Imports System.Text
Imports System.Globalization
Imports System.IO
Imports System.Diagnostics
Imports System.Threading
Imports System.ComponentModel
Namespace ProcessAsyncStreamSamples
Class ProcessAsyncErrorRedirection
' Define static variables shared by class methods.
Private Shared streamError As StreamWriter = Nothing
Private Shared netErrorFile As String = ""
Private Shared netOutput As StringBuilder = Nothing
Private Shared errorRedirect As Boolean = False
Private Shared errorsWritten As Boolean = False
Public Shared Sub RedirectNetCommandStreams()
Dim netArguments As String
Dim netProcess As Process
' Get the input computer name.
Console.WriteLine("Enter the computer name for the net view command:")
netArguments = Console.ReadLine().ToUpper(CultureInfo.InvariantCulture)
If String.IsNullOrEmpty(netArguments) Then
' Default to the help command if there is
' not an input argument.
netArguments = "/?"
End If
' Check if errors should be redirected to a file.
errorsWritten = False
Console.WriteLine("Enter a fully qualified path to an error log file")
Console.WriteLine(" or just press Enter to write errors to console:")
netErrorFile = Console.ReadLine().ToUpper(CultureInfo.InvariantCulture)
If Not String.IsNullOrEmpty(netErrorFile) Then
errorRedirect = True
End If
' Note that at this point, netArguments and netErrorFile
' are set with user input. If the user did not specify
' an error file, then errorRedirect is set to false.
' Initialize the process and its StartInfo properties.
netProcess = New Process()
netProcess.StartInfo.FileName = "Net.exe"
' Build the net command argument list.
netProcess.StartInfo.Arguments = String.Format("view {0}", _
netArguments)
' Set UseShellExecute to false for redirection.
netProcess.StartInfo.UseShellExecute = False
' Redirect the standard output of the net command.
' Read the stream asynchronously using an event handler.
netProcess.StartInfo.RedirectStandardOutput = True
AddHandler netProcess.OutputDataReceived, _
AddressOf NetOutputDataHandler
netOutput = new StringBuilder()
If errorRedirect Then
' Redirect the error output of the net command.
netProcess.StartInfo.RedirectStandardError = True
AddHandler netProcess.ErrorDataReceived, _
AddressOf NetErrorDataHandler
Else
' Do not redirect the error output.
netProcess.StartInfo.RedirectStandardError = False
End If
Console.WriteLine(ControlChars.Lf + "Starting process: NET {0}", _
netProcess.StartInfo.Arguments)
If errorRedirect Then
Console.WriteLine("Errors will be written to the file {0}", _
netErrorFile)
End If
' Start the process.
netProcess.Start()
' Start the asynchronous read of the standard output stream.
netProcess.BeginOutputReadLine()
If errorRedirect Then
' Start the asynchronous read of the standard
' error stream.
netProcess.BeginErrorReadLine()
End If
' Let the net command run, collecting the output.
netProcess.WaitForExit()
If Not streamError Is Nothing Then
' Close the error file.
streamError.Close()
Else
' Set errorsWritten to false if the stream is not
' open. Either there are no errors, or the error
' file could not be opened.
errorsWritten = False
End If
If netOutput.Length > 0 Then
' If the process wrote more than just
' white space, write the output to the console.
Console.WriteLine()
Console.WriteLine("Public network shares from net view:")
Console.WriteLine()
Console.WriteLine(netOutput)
Console.WriteLine()
End If
If errorsWritten Then
' Signal that the error file had something
' written to it.
Dim errorOutput As String()
errorOutput = File.ReadAllLines(netErrorFile)
If errorOutput.Length > 0 Then
Console.WriteLine(ControlChars.Lf + _
"The following error output was appended to {0}.", _
netErrorFile)
Dim errLine as String
For Each errLine in errorOutput
Console.WriteLine(" {0}", errLine)
Next
Console.WriteLine()
End If
End If
netProcess.Close()
End Sub
Private Shared Sub NetOutputDataHandler(sendingProcess As Object, _
outLine As DataReceivedEventArgs)
' Collect the net view command output.
If Not String.IsNullOrEmpty(outLine.Data) Then
' Add the text to the collected output.
netOutput.Append(Environment.NewLine + " " + outLine.Data)
End If
End Sub
Private Shared Sub NetErrorDataHandler(sendingProcess As Object, _
errLine As DataReceivedEventArgs)
' Write the error text to the file if there is something to
' write and an error file has been specified.
If Not String.IsNullOrEmpty(errLine.Data) Then
If Not errorsWritten Then
If streamError Is Nothing Then
' Open the file.
Try
streamError = New StreamWriter(netErrorFile, true)
Catch e As Exception
Console.WriteLine("Could not open error file!")
Console.WriteLine(e.Message.ToString())
End Try
End If
If Not streamError Is Nothing Then
' Write a header to the file if this is the first
' call to the error output handler.
streamError.WriteLine()
streamError.WriteLine(DateTime.Now.ToString())
streamError.WriteLine("Net View error output:")
End If
errorsWritten = True
End If
If Not streamError Is Nothing Then
' Write redirected errors to the file.
streamError.WriteLine(errLine.Data)
streamError.Flush()
End If
End If
End Sub
End Class
End Namespace
Açıklamalar
Akış StandardError zaman uyumlu veya zaman uyumsuz olarak okunabilir. , Readve ReadLine gibi ReadToEndyöntemler, işlemin hata çıktı akışında zaman uyumlu okuma işlemleri gerçekleştirir. İlişkili yazma işlemi akışına yazılana Process veya akışı kapatana kadar StandardError bu zaman uyumlu okuma işlemleri tamamlanmaz.
Buna karşılık, BeginErrorReadLine akışta StandardError zaman uyumsuz okuma işlemlerini başlatır. Bu yöntem, akış çıkışı için belirlenen olay işleyicisini etkinleştirir ve hemen çağırana geri döner ve akış çıkışı olay işleyicisine yönlendirilirken diğer işleri gerçekleştirebilir.
üzerinde zaman uyumsuz okuma işlemleri StandardError gerçekleştirmek için Process şu adımları izleyin:
UseShellExecute değerini
falseolarak ayarlayın.RedirectStandardError değerini
trueolarak ayarlayın.Olaya olay işleyicinizi ErrorDataReceived ekleyin. Olay işleyicisi temsilci imzası ile System.Diagnostics.DataReceivedEventHandler eşleşmelidir.
Process öğesini başlatın.
için çağrısında BeginErrorReadLine bulunur Process. Bu çağrı üzerinde StandardErrorzaman uyumsuz okuma işlemlerini başlatır.
Zaman uyumsuz okuma işlemleri başlatıldığında, ilişkili Process akışına her metin satırı yazdığında olay işleyicisi çağrılır StandardError .
çağırarak CancelErrorReadzaman uyumsuz bir okuma işlemini iptal edebilirsiniz. Okuma işlemi çağıran veya olay işleyicisi tarafından iptal edilebilir. İptal ettikten sonra, zaman uyumsuz okuma işlemlerini sürdürmek için yeniden çağırabilirsiniz BeginErrorReadLine .
Note
Yeniden yönlendirilen bir akışta zaman uyumsuz ve zaman uyumlu okuma işlemlerini karıştıramazsınız. Bir öğesinin yeniden yönlendirilen akışı Process zaman uyumsuz veya zaman uyumlu modda açıldıktan sonra, bu akıştaki diğer tüm okuma işlemleri aynı modda olmalıdır. Örneğin, akışta BeginErrorReadLine çağrısıyla ReadLine (veya tam tersi) takip StandardError etmeyin. Ancak, farklı modlarda iki farklı akışı okuyabilirsiniz. Örneğin, akışı çağırabilir BeginErrorReadLine ve ardından çağırabilirsiniz ReadLineStandardOutput .
