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Runspace09 Sample

This sample shows how to add a script to the pipeline of a System.Management.Automation.PowerShell object and how to run the script asynchronously. Events are used to handle the output of the script.

Requirements

This sample requires Windows PowerShell 2.0.

Demonstrates

This sample demonstrates the following.

Example

This sample runs to run a script that generates the numbers from 1 to 10 with delays between each number. The script is run asynchronously and events are used to handle the output.

namespace Microsoft.Samples.PowerShell.Runspaces
{
  using System;
  using System.Collections.Generic;
  using System.Collections.ObjectModel;
  using System.Diagnostics;
  using System.Management.Automation;
  using System.Management.Automation.Runspaces;
  using PowerShell = System.Management.Automation.PowerShell;

  /// <summary>
  /// This class contains the Main entry point for this host application.
  /// </summary>
  internal class Runspace09
  {
    /// <summary>
    /// This sample shows how to use a PowerShell object to run a
    /// script that generates the numbers from 1 to 10 with delays
    /// between each number. The pipeline of the PowerShell object
    /// is run asynchronously and events are used to handle the output.
    /// </summary>
    /// <param name="args">The parameter is not used.</param>
    /// <remarks>
    /// This sample demonstrates the following:
    /// 1. Creating a PowerShell object.
    /// 2. Adding a script to the pipeline of the PowerShell object.
    /// 3. Using the BeginInvoke method to run the pipeline asynchronously.
    /// 4. Using the events of the PowerShell object to process the
    ///    output of the script.
    /// 5. Using the PowerShell.Stop() method to interrupt the invocation of
    ///    the pipeline.
    /// </remarks>
    private static void Main(string[] args)
    {
      Console.WriteLine("Print the numbers from 1 to 10. Hit any key to halt processing\n");

      using (PowerShell powershell = PowerShell.Create())
      {
        // Add a script to the PowerShell object. The script generates the
        // numbers from 1 to 10 in half second intervals.
        powershell.AddScript("1..10 | foreach {$_ ; Start-Sleep -Milli 500}");

        // Add the event handlers.  If we did not care about hooking the DataAdded
        // event, we would let BeginInvoke create the output stream for us.
        PSDataCollection<PSObject> output = new PSDataCollection<PSObject>();
        output.DataAdded += new EventHandler<DataAddedEventArgs>(Output_DataAdded);
        powershell.InvocationStateChanged += new EventHandler<PSInvocationStateChangedEventArgs>(Powershell_InvocationStateChanged);

        // Invoke the pipeline asynchronously.
        IAsyncResult asyncResult = powershell.BeginInvoke<PSObject, PSObject>(null, output);

        // Wait for things to happen. If the user hits a key before the
        // script has completed, then call the PowerShell Stop() method
        // to halt processing.
        Console.ReadKey();
        if (powershell.InvocationStateInfo.State != PSInvocationState.Completed)
        {
          // Stop the invocation of the pipeline.
          Console.WriteLine("\nStopping the pipeline!\n");
          powershell.Stop();

          // Wait for the Windows PowerShell state change messages to be displayed.
          System.Threading.Thread.Sleep(500);
          Console.WriteLine("\nPress a key to exit");
          Console.ReadKey();
        }
      }
    }

    /// <summary>
    /// The output data added event handler. This event is called when
    /// data is added to the output pipe. It reads the data that is
    /// available and displays it on the console.
    /// </summary>
    /// <param name="sender">The output pipe this event is associated with.</param>
    /// <param name="e">Parameter is not used.</param>
    private static void Output_DataAdded(object sender, DataAddedEventArgs e)
    {
      PSDataCollection<PSObject> myp = (PSDataCollection<PSObject>)sender;

      Collection<PSObject> results = myp.ReadAll();
      foreach (PSObject result in results)
      {
        Console.WriteLine(result.ToString());
      }
    }

    /// <summary>
    /// This event handler is called when the pipeline state is changed.
    /// If the state change is to Completed, the handler issues a message
    /// asking the user to exit the program.
    /// </summary>
    /// <param name="sender">This parameter is not used.</param>
    /// <param name="e">The PowerShell state information.</param>
    private static void Powershell_InvocationStateChanged(object sender, PSInvocationStateChangedEventArgs e)
    {
      Console.WriteLine("PowerShell object state changed: state: {0}\n", e.InvocationStateInfo.State);
      if (e.InvocationStateInfo.State == PSInvocationState.Completed)
      {
        Console.WriteLine("Processing completed, press a key to exit!");
      }
    }
  }
}

See Also

Writing a Windows PowerShell Host Application