Process.BeginOutputReadLine Méthode

public:
 void BeginOutputReadLine();

[System.Runtime.InteropServices.ComVisible(false)]
public void BeginOutputReadLine();

public void BeginOutputReadLine();

[<System.Runtime.InteropServices.ComVisible(false)>]
member this.BeginOutputReadLine : unit -> unit

member this.BeginOutputReadLine : unit -> unit

Public Sub BeginOutputReadLine ()

Attributs

ComVisibleAttribute

Exceptions

Exemples

L’exemple suivant montre comment effectuer des opérations de lecture asynchrones sur le flux redirigé StandardOutput de la sort commande. La sort commande est une application console qui lit et trie l’entrée de texte.

L’exemple crée un délégué d’événement pour le SortOutputHandler gestionnaire d’événements et l’associe à l’événement OutputDataReceived . Le gestionnaire d’événements reçoit des lignes de texte du flux redirigé StandardOutput , met en forme le texte et écrit le texte à l’écran.

// Define the namespaces used by this sample.
using System;
using System.Text;
using System.IO;
using System.Diagnostics;
using System.Threading;
using System.ComponentModel;

namespace ProcessAsyncStreamSamples
{
    class SortOutputRedirection
    {
        // Define static variables shared by class methods.
        private static StringBuilder sortOutput = null;
        private static int numOutputLines = 0;

        public static void SortInputListText()
        {
            // Initialize the process and its StartInfo properties.
            // The sort command is a console application that
            // reads and sorts text input.

            Process sortProcess = new Process();
            sortProcess.StartInfo.FileName = "Sort.exe";

            // Set UseShellExecute to false for redirection.
            sortProcess.StartInfo.UseShellExecute = false;

            // Redirect the standard output of the sort command.
            // This stream is read asynchronously using an event handler.
            sortProcess.StartInfo.RedirectStandardOutput = true;
            sortOutput = new StringBuilder();

            // Set our event handler to asynchronously read the sort output.
            sortProcess.OutputDataReceived += SortOutputHandler;

            // Redirect standard input as well.  This stream
            // is used synchronously.
            sortProcess.StartInfo.RedirectStandardInput = true;

            // Start the process.
            sortProcess.Start();

            // Use a stream writer to synchronously write the sort input.
            StreamWriter sortStreamWriter = sortProcess.StandardInput;

            // Start the asynchronous read of the sort output stream.
            sortProcess.BeginOutputReadLine();

            // Prompt the user for input text lines.  Write each
            // line to the redirected input stream of the sort command.
            Console.WriteLine("Ready to sort up to 50 lines of text");

            String inputText;
            int numInputLines = 0;
            do
            {
                Console.WriteLine("Enter a text line (or press the Enter key to stop):");

                inputText = Console.ReadLine();
                if (!String.IsNullOrEmpty(inputText))
                {
                    numInputLines++;
                    sortStreamWriter.WriteLine(inputText);
                }
            }
            while (!String.IsNullOrEmpty(inputText) && (numInputLines < 50));
            Console.WriteLine("<end of input stream>");
            Console.WriteLine();

            // End the input stream to the sort command.
            sortStreamWriter.Close();

            // Wait for the sort process to write the sorted text lines.
            sortProcess.WaitForExit();

            if (numOutputLines > 0)
            {
                // Write the formatted and sorted output to the console.
                Console.WriteLine($" Sort results = {numOutputLines} sorted text line(s) ");
                Console.WriteLine("----------");
                Console.WriteLine(sortOutput);
            }
            else
            {
                Console.WriteLine(" No input lines were sorted.");
            }

            sortProcess.Close();
        }

        private static void SortOutputHandler(object sendingProcess,
            DataReceivedEventArgs outLine)
        {
            // Collect the sort command output.
            if (!String.IsNullOrEmpty(outLine.Data))
            {
                numOutputLines++;

                // Add the text to the collected output.
                sortOutput.Append(Environment.NewLine +
                    $"[{numOutputLines}] - {outLine.Data}");
            }
        }
    }
}

namespace ProcessAsyncStreamSamples
{

    class ProcessSampleMain
    {
        /// The main entry point for the application.
        static void Main()
        {
            try
            {
                SortOutputRedirection.SortInputListText();
            }
            catch (InvalidOperationException e)
            {
                Console.WriteLine("Exception:");
                Console.WriteLine(e);
            }
        }
    }
}

// Define the namespaces used by this sample.
open System
open System.Text
open System.Diagnostics

// Define variables shared by class methods.
let mutable sortOutput = StringBuilder()
let mutable numOutputLines = 0;

let sortOutputHandler (sendingProcess: obj) (outLine: DataReceivedEventArgs) =
    // Collect the sort command output.
    if String.IsNullOrEmpty outLine.Data |> not then
        numOutputLines <- numOutputLines + 1
        // Add the text to the collected output.
        sortOutput.Append(Environment.NewLine + $"[{numOutputLines}] - {outLine.Data}") |> ignore

let sortInputListText () =
    // Initialize the process and its StartInfo properties.
    // The sort command is a console application that
    // reads and sorts text input.

    let sortProcess = new Process();
    sortProcess.StartInfo.FileName <- "Sort.exe"

    // Set UseShellExecute to false for redirection.
    sortProcess.StartInfo.UseShellExecute <- false;

    // Redirect the standard output of the sort command.
    // This stream is read asynchronously using an event handler.
    sortProcess.StartInfo.RedirectStandardOutput <- true;
    sortOutput <- StringBuilder();

    // Set our event handler to asynchronously read the sort output.
    sortProcess.OutputDataReceived.AddHandler sortOutputHandler

    // Redirect standard input as well.  This stream
    // is used synchronously.
    sortProcess.StartInfo.RedirectStandardInput <- true;

    // Start the process.
    sortProcess.Start() |> ignore

    // Use a stream writer to synchronously write the sort input.
    let sortStreamWriter = sortProcess.StandardInput;

    // Start the asynchronous read of the sort output stream.
    sortProcess.BeginOutputReadLine();

    // Prompt the user for input text lines.  Write each
    // line to the redirected input stream of the sort command.
    printfn "Ready to sort up to 50 lines of text"

    let mutable inputText = ""
    let mutable numInputLines = 0
    while String.IsNullOrEmpty inputText do
        printfn "Enter a text line (or press the Enter key to stop):"

        inputText <- Console.ReadLine()
        if String.IsNullOrEmpty inputText |> not then
            numInputLines <- numInputLines + 1
            sortStreamWriter.WriteLine inputText

    printfn "<end of input stream>\n"

    // End the input stream to the sort command.
    sortStreamWriter.Close()

    // Wait for the sort process to write the sorted text lines.
    sortProcess.WaitForExit()

    if numOutputLines > 0 then
        // Write the formatted and sorted output to the console.
        printfn $" Sort results = {numOutputLines} sorted text line(s) "
        printfn "----------"
        printfn $"{sortOutput}"
    else
        printfn " No input lines were sorted."

    sortProcess.Close();

// The main entry point for the application.
do
    try
        sortInputListText ()
    with :? InvalidOperationException as e ->
        printfn "Exception:"
        printfn $"{e}"

' Define the namespaces used by this sample.
Imports System.Text
Imports System.IO
Imports System.Diagnostics
Imports System.Threading
Imports System.ComponentModel

Namespace ProcessAsyncStreamSamples

    Class ProcessAsyncOutputRedirection
        ' Define static variables shared by class methods.
        Private Shared sortOutput As StringBuilder = Nothing
        Private Shared numOutputLines As Integer = 0

        Public Shared Sub SortInputListText()

            ' Initialize the process and its StartInfo properties.
            ' The sort command is a console application that
            ' reads and sorts text input.
            Dim sortProcess As New Process()
            sortProcess.StartInfo.FileName = "Sort.exe"

            ' Set UseShellExecute to false for redirection.
            sortProcess.StartInfo.UseShellExecute = False

            ' Redirect the standard output of the sort command.  
            ' Read the stream asynchronously using an event handler.
            sortProcess.StartInfo.RedirectStandardOutput = True
            sortOutput = New StringBuilder()

            ' Set our event handler to asynchronously read the sort output.
            AddHandler sortProcess.OutputDataReceived, AddressOf SortOutputHandler

            ' Redirect standard input as well.  This stream
            ' is used synchronously.
            sortProcess.StartInfo.RedirectStandardInput = True

            ' Start the process.
            sortProcess.Start()

            ' Use a stream writer to synchronously write the sort input.
            Dim sortStreamWriter As StreamWriter = sortProcess.StandardInput

            ' Start the asynchronous read of the sort output stream.
            sortProcess.BeginOutputReadLine()

            ' Prompt the user for input text lines.  Write each 
            ' line to the redirected input stream of the sort command.
            Console.WriteLine("Ready to sort up to 50 lines of text")

            Dim inputText As String
            Dim numInputLines As Integer = 0
            Do
                Console.WriteLine("Enter a text line (or press the Enter key to stop):")

                inputText = Console.ReadLine()
                If Not String.IsNullOrEmpty(inputText) Then
                    numInputLines += 1
                    sortStreamWriter.WriteLine(inputText)
                End If
            Loop While Not String.IsNullOrEmpty(inputText) AndAlso numInputLines < 50
            Console.WriteLine("<end of input stream>")
            Console.WriteLine()

            ' End the input stream to the sort command.
            sortStreamWriter.Close()

            ' Wait for the sort process to write the sorted text lines.
            sortProcess.WaitForExit()

            If Not String.IsNullOrEmpty(numOutputLines) Then
                ' Write the formatted and sorted output to the console.
                Console.WriteLine($" Sort results = {numOutputLines} sorted text line(s) ")
                Console.WriteLine("----------")
                Console.WriteLine(sortOutput)
            Else
                Console.WriteLine(" No input lines were sorted.")
            End If

            sortProcess.Close()
        End Sub

        Private Shared Sub SortOutputHandler(sendingProcess As Object,
           outLine As DataReceivedEventArgs)

            ' Collect the sort command output.
            If Not String.IsNullOrEmpty(outLine.Data) Then
                numOutputLines += 1

                ' Add the text to the collected output.
                sortOutput.Append(Environment.NewLine +
                    $"[{numOutputLines}] - {outLine.Data}")
            End If
        End Sub
    End Class
End Namespace

Namespace ProcessAsyncStreamSamples

    Class ProcessSampleMain

        ' The main entry point for the application.
        Shared Sub Main()
            Try
                ProcessAsyncOutputRedirection.SortInputListText()

            Catch e As InvalidOperationException
                Console.WriteLine("Exception:")
                Console.WriteLine(e)
            End Try
        End Sub
    End Class  'ProcessSampleMain
End Namespace 'Process_AsyncStream_Sample

Remarques

Le StandardOutput flux peut être lu de manière synchrone ou asynchrone. Méthodes telles que Read, ReadLineet ReadToEnd effectuer des opérations de lecture synchrones sur le flux de sortie du processus. Ces opérations de lecture synchrones ne se terminent pas tant que les écritures associées Process n’ont pas été effectuées dans son StandardOutput flux ou ferment le flux.

En revanche, BeginOutputReadLine démarre les opérations de lecture asynchrones sur le StandardOutput flux. Cette méthode active un gestionnaire d’événements désigné pour la sortie du flux et retourne immédiatement à l’appelant, ce qui peut effectuer d’autres tâches pendant que la sortie du flux est dirigée vers le gestionnaire d’événements.

Procédez comme suit pour effectuer des opérations de lecture asynchrones sur StandardOutput un Process :

1. Affectez la valeur UseShellExecute à false.

2. Affectez la valeur RedirectStandardOutput à true.

3. Ajoutez votre gestionnaire d’événements à l’événement OutputDataReceived . Le gestionnaire d’événements doit correspondre à la System.Diagnostics.DataReceivedEventHandler signature de délégué.

4. Démarrez Process.

5. Appel BeginOutputReadLine pour le Process. Cet appel démarre les opérations de lecture asynchrones sur StandardOutput.

Lorsque les opérations de lecture asynchrones démarrent, le gestionnaire d’événements est appelé chaque fois que l’associé Process écrit une ligne de texte dans son StandardOutput flux.

Vous pouvez annuler une opération de lecture asynchrone en appelant CancelOutputRead. L’opération de lecture peut être annulée par l’appelant ou par le gestionnaire d’événements. Après l’annulation, vous pouvez appeler BeginOutputReadLine à nouveau pour reprendre les opérations de lecture asynchrones.

Voir aussi

• RedirectStandardOutput
• StandardOutput
• OutputDataReceived
• DataReceivedEventHandler
• CancelOutputRead()