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Windows PowerShell02 Sample


This sample shows how to run commands asynchronously by using the runspaces of a runspace pool. The sample generates a list of commands, and then runs those commands while the Windows PowerShell engine opens a runspace from the pool when it is needed.


  • This sample requires Windows PowerShell 2.0.


This sample demonstrates the following:

  • Creating a RunspacePool object with a minimum and maximum number of runspaces allowed to be open at the same time.

  • Creating a list of commands.

  • Running the commands asynchronously.

  • Calling the GetAvailableRunspaces method to see how many runspaces are free.

  • Capturing the command output with the EndInvoke method.


This sample shows how to open the runspaces of a runspace pool, and how to asynchronously run commands in those runspaces.

namespace Sample
  using System;
  using System.Collections;
  using System.Collections.Generic;
  using System.Management.Automation;
  using System.Management.Automation.Runspaces;

  /// <summary>
  /// This class contains the Main entry point for the application.
  /// </summary>
  internal class PowerShell02
    /// <summary>
    /// Runs numerous commands with the help of a runspace pool.
    /// </summary>
    /// <param name="args">This parameter is unused.</param>
    private static void Main(string[] args)
      // Creating and opening runspace pool. A minimum of 1 runspace and a maximum of 
      // 5 runspaces can be opened at the same time.
      RunspacePool runspacePool = RunspaceFactory.CreateRunspacePool(1, 5);

      using (runspacePool)
        // Define the commands to be run.
        List<PowerShell> powerShellCommands = new List<PowerShell>();

        // The command results.
        List<IAsyncResult> powerShellCommandResults = new List<IAsyncResult>();

        // The maximum number of runspaces that can be opened at one tine is 
        // is 5, but we can queue up many more commands that will use the 
        // runspace pool.
        for (int i = 0; i < 100; i++)
          // Using a PowerShell object, run the commands.
          PowerShell powershell = PowerShell.Create();

          // Instead of setting the Runspace property of powershell,
          // the RunspacePool property is used. That is the only difference
          // between running commands with a runspace and running commands 
          // with a runspace pool.
          powershell.RunspacePool = runspacePool;

          // The script to be run outputs a sequence number and the number of available runspaces 
          // in the pool.
          string script = String.Format(
                        "write-output ' Command: {0}, Available Runspaces: {1}'",

          // The three lines below look the same running with a runspace or 
          // with a runspace pool.

        // Collect the results.
        for (int i = 0; i < 100; i++)
          // EndInvoke will wait for each command to finish, so we will be getting the commands
          // in the same 0 to 99 order that they have been invoked with BeginInvoke.
          PSDataCollection<PSObject> results = powerShellCommands[i].EndInvoke(powerShellCommandResults[i]);

          // Print all the results. One PSObject with a plain string is the expected result.

    /// <summary>
    /// Iterates through a collection printing all items.
    /// </summary>
    /// <param name="collection">collection to be printed</param>
    private static void PrintCollection(IList collection)
      foreach (object obj in collection)
        Console.WriteLine("PowerShell Result: {0}", obj);