Process.ErrorDataReceived Process.ErrorDataReceived Process.ErrorDataReceived Process.ErrorDataReceived Event

Definizione

Si verifica quando un'applicazione scrive nel proprio flusso StandardError reindirizzato.Occurs when an application writes to its redirected StandardError stream.

public:
 event System::Diagnostics::DataReceivedEventHandler ^ ErrorDataReceived;
[System.ComponentModel.Browsable(true)]
public event System.Diagnostics.DataReceivedEventHandler ErrorDataReceived;
member this.ErrorDataReceived : System.Diagnostics.DataReceivedEventHandler 
Public Custom Event ErrorDataReceived As DataReceivedEventHandler 
Attributi

Esempi

L'esempio seguente usa il net view comando per elencare le risorse di rete disponibili in un computer remoto.The following example uses the net view command to list the available network resources on a remote computer. L'utente fornisce il nome del computer di destinazione come argomento della riga di comando.The user supplies the target computer name as a command-line argument. L'utente può fornire anche un nome di file per l'output di errore.The user can also supply a file name for error output. L'esempio raccoglie l'output del comando net, attende il completamento del processo e quindi scrive l'output risultante nella console.The example collects the output of the net command, waits for the process to finish, and then writes the output results to the console. Se l'utente fornisce il file di errore facoltativo, vengono scritti gli errori nel file.If the user supplies the optional error file, the example writes errors to the file.

// Define the namespaces used by this sample.
#using <System.dll>

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
using namespace System::IO;
using namespace System::Diagnostics;
using namespace System::Threading;
using namespace System::ComponentModel;

ref class ProcessNetStreamRedirection
{
private:
   // Define static variables shared by class methods.
   static StreamWriter^ streamError = nullptr;
   static String^ netErrorFile = "";
   static StringBuilder^ netOutput = nullptr;
   static bool errorRedirect = false;
   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 = gcnew 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 += gcnew DataReceivedEventHandler( NetOutputDataHandler );
      netOutput = gcnew StringBuilder;
      if ( errorRedirect )
      {
         
         // Redirect the error output of the net command. 
         netProcess->StartInfo->RedirectStandardError = true;
         netProcess->ErrorDataReceived += gcnew 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 != nullptr )
      {
         // 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->ToString() );
      }

      if ( errorsWritten )
      {
         // Signal that the error file had something 
         // written to it.
         array<String^>^errorOutput = File::ReadAllLines( netErrorFile );
         if ( errorOutput->Length > 0 )
         {
            Console::WriteLine( "\nThe following error output was appended to {0}.",
               netErrorFile );
            System::Collections::IEnumerator^ myEnum = errorOutput->GetEnumerator();
            while ( myEnum->MoveNext() )
            {
               String^ errLine = safe_cast<String^>(myEnum->Current);
               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->AppendFormat(  "\n  {0}", outLine->Data );
      }
   }

   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 == nullptr )
            {
               // Open the file.
               try
               {
                  streamError = gcnew StreamWriter( netErrorFile,true );
               }
               catch ( Exception^ e ) 
               {
                  Console::WriteLine(  "Could not open error file!" );
                  Console::WriteLine( e->Message->ToString() );
               }
            }

            if ( streamError != nullptr )
            {
               // 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 != nullptr )
         {
            // Write redirected errors to the file.
            streamError->WriteLine( errLine->Data );
            streamError->Flush();
         }
      }
   }
};
// 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.
Imports System
Imports System.Text
Imports System.Globalization
Imports System.IO
Imports System.Diagnostics
Imports System.Threading
Imports System.ComponentModel
Imports Microsoft.VisualBasic


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 

Commenti

Il ErrorDataReceived evento indica che il processo associato ha scritto nel proprio flusso StandardError flusso.The ErrorDataReceived event indicates that the associated process has written to its redirected StandardError stream.

L'evento si verifica solo durante le operazioni di lettura asincrone sul StandardError.The event only occurs during asynchronous read operations on StandardError. Per avviare operazioni di lettura asincrona, è necessario reindirizzare il StandardError flusso di un Process, aggiungere il gestore eventi per il ErrorDataReceived evento, quindi chiamare BeginErrorReadLine.To start asynchronous read operations, you must redirect the StandardError stream of a Process, add your event handler to the ErrorDataReceived event, and call BeginErrorReadLine. Successivamente, il ErrorDataReceived segnali di evento ogni volta che il processo scrive una riga in reindirizzato StandardError streaming, fino a quando il processo viene chiuso o chiama CancelErrorRead.Thereafter, the ErrorDataReceived event signals each time the process writes a line to the redirected StandardError stream, until the process exits or calls CancelErrorRead.

Nota

L'applicazione di elaborazione dell'output asincrono deve chiamare il WaitForExit() metodo per assicurarsi che il buffer di output è stato scaricato.The application that is processing the asynchronous output should call the WaitForExit() method to ensure that the output buffer has been flushed. Si noti che se si specifica un timeout utilizzando il WaitForExit(Int32) overload viene non assicurarsi che il buffer di output è stato scaricato.Note that specifying a timeout by using the WaitForExit(Int32) overload does not ensure the output buffer has been flushed.

Sicurezza

LinkDemand
per un'attendibilità totale per il chiamante immediato.for full trust for the immediate caller. Impossibile utilizzare questo membro in codice parzialmente attendibile.This member cannot be used by partially trusted code.

Si applica a

Vedi anche