Process.ErrorDataReceived Zdarzenie

Definicja

Przestrzeń nazw:

System.Diagnostics

Zestaw:

System.Diagnostics.Process.dll

Źródło:

Process.cs

Występuje, gdy aplikacja zapisuje w przekierowanym StandardError strumieniu.

public:
 event System::Diagnostics::DataReceivedEventHandler ^ ErrorDataReceived;

public event System.Diagnostics.DataReceivedEventHandler? ErrorDataReceived;

member this.ErrorDataReceived : System.Diagnostics.DataReceivedEventHandler 

Public Custom Event ErrorDataReceived As DataReceivedEventHandler 

Typ zdarzenia

DataReceivedEventHandler

Przykłady

W poniższym przykładzie użyto polecenia , net view aby wyświetlić listę dostępnych zasobów sieciowych na komputerze zdalnym. Użytkownik dostarcza nazwę komputera docelowego jako argument wiersza polecenia. Użytkownik może również podać nazwę pliku dla danych wyjściowych błędu. Przykład zbiera dane wyjściowe polecenia net, czeka na zakończenie procesu, a następnie zapisuje wyniki wyjściowe w konsoli. Jeśli użytkownik dostarcza opcjonalny plik błędu, przykład zapisuje błędy w pliku.

// 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.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

Uwagi

Zdarzenie ErrorDataReceived wskazuje, że skojarzony Process zapisał wiersz zakończony nowym wierszem (zwrot karetki (CR), kanałem informacyjnym wiersza (LF) lub CR+LF) do przekierowanego strumienia StandardError .

Zdarzenie występuje tylko podczas asynchronicznych operacji odczytu w systemie StandardError. Aby uruchomić operacje odczytu asynchronicznego, należy przekierować StandardError strumień Processprogramu obsługi zdarzeń do zdarzenia i wywołać metodę ErrorDataReceivedBeginErrorReadLine. Następnie zdarzenie sygnalizuje za każdym razem, ErrorDataReceived gdy proces zapisuje wiersz do przekierowanego StandardError strumienia, aż proces zakończy działanie lub wywoła CancelErrorReadpolecenie .

Uwaga

Aplikacja, która przetwarza dane wyjściowe asynchroniczne, powinna wywołać metodę WaitForExit() , aby upewnić się, że bufor wyjściowy został opróżniony. Należy pamiętać, że określenie limitu czasu przy użyciu przeciążenia nie zapewnia opróżnienia buforu wyjściowegoWaitForExit(Int32).

Zobacz też

• RedirectStandardError
• StandardError
• BeginErrorReadLine()
• CancelErrorRead()
• DataReceivedEventHandler