RunSpace07 Code Sample

Here is the source code for the Runspace07 sample described in Creating a Console Application That Adds Commands to a Pipeline. This sample application creates a runspace, creates a pipeline, adds two commands to the pipeline, and then executes the pipeline. The commands added to the pipeline are the Get-Process and Measure-Object cmdlets.

Note

You can download the C# source file (runspace07.cs) using the Microsoft Windows Software Development Kit for Windows Vista and Microsoft .NET Framework 3.0 Runtime Components. For download instructions, see How to Install Windows PowerShell and Download the Windows PowerShell SDK. The downloaded source files are available in the <PowerShell Samples> directory.

Code Sample

namespace Microsoft.Samples.PowerShell.Runspaces
{
  using System;
  using System.Collections.ObjectModel;
  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 Runspace07
  {
    /// <summary>
    /// This sample shows how to create a runspace and how to run 
    /// commands using a PowerShell object. It builds a pipeline 
    /// that runs the get-process cmdlet, which is piped to the measure-object 
    /// cmdlet to count the number of processes running on the system.
    /// </summary>
    /// <param name="args">Parameter is not used.</param>
    /// <remarks>
    /// This sample demonstrates the following:
    /// 1. Creating a runspace using the RunspaceFactory class.
    /// 2. Creating a PowerShell object
    /// 3. Adding individual cmdlets to the PowerShell object.
    /// 4. Running the cmdlets synchronously.
    /// 5. Working with PSObject objects to extract properties 
    ///    from the objects returned by the cmdlets.
    /// </remarks>
    private static void Main(string[] args)
    {
      Collection<PSObject> result;     // Will hold the result
                                       // of running the cmdlets.

      // Create a runspace. We can not use the RunspaceInvoke class 
      // because we need to get at the underlying runspace to  
      // explicitly add the commands. Notice that no PSHost object is 
      // supplied to the CreateRunspace method so the default host is 
      // used. See the Host samples for more information on creating 
      // your own custom host.
      using (Runspace myRunSpace = RunspaceFactory.CreateRunspace())
      {
        myRunSpace.Open();

        // Create a PowerShell object and specify the runspace. 
        PowerShell powershell = PowerShell.Create();
        powershell.Runspace = myRunSpace;

        // Use the using statement so we dispose of the PowerShell object
        // when we're done.
        using (powershell)
        {
          // Add the get-process cmdlet to the PowerShell object. Notice 
          // we are specify the name of the cmdlet, not a script.
          powershell.AddCommand("get-process");

          // Add the measure-object cmdlet to count the number
          // of objects being returned. Commands are always added to the end 
          // of the pipeline.
          powershell.AddCommand("measure-object");

          // Run the cmdlets synchronously and save the objects returned.
          result = powershell.Invoke();
        }

        // Even after disposing of the pipeLine, we still need to set 
        // the powershell variable to null so that the garbage collector
        // can clean it up.
        powershell = null;

        // Display the results of running the commands (checking that
        // everything is ok first.
        if (result == null || result.Count != 1)
        {
          throw new InvalidOperationException(
                    "pipeline.Invoke() returned the wrong number of objects");
        }

        PSMemberInfo count = result[0].Properties["Count"];
        if (count == null)
        {
          throw new InvalidOperationException(
                    "The object returned doesn't have a 'count' property");
        }

        Console.WriteLine(
                   "Runspace07: The get-process cmdlet returned {0} objects",
                   count.Value);

        // Close the runspace to release any resources.
        myRunSpace.Close();
      }
      
      System.Console.WriteLine("Hit any key to exit...");
      System.Console.ReadKey();
    }
  }
}

See Also

Windows PowerShell Programmer's Guide

Windows PowerShell SDK