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Creating a constrained runspace

For performance or security reasons, you might want to restrict the Windows PowerShell commands available to your host application. To do this you create an empty System.Management.Automation.Runspaces.Initialsessionstate by calling the System.Management.Automation.Runspaces.Initialsessionstate.Create* method, and then add only the commands you want available.

Using a runspace that loads only the commands that you specify provides significantly improved performance.

You use the methods of the System.Management.Automation.Runspaces.Sessionstatecmdletentry class to define cmdlets for the initial session state.

You can also make commands private. Private commands can be used by the host application, but not by users of the application.

Adding commands to an empty runspace

The following example demonstrates how to create an empty InitialSessionState and add commands to it.

namespace Microsoft.Samples.PowerShell.Runspaces
  using System;
  using System.Collections.ObjectModel;
  using System.Management.Automation;
  using System.Management.Automation.Runspaces;
  using Microsoft.PowerShell.Commands;
  using PowerShell = System.Management.Automation.PowerShell;

  /// <summary>
  /// This class contains the Main entry point for the application.
  /// </summary>
  internal class Runspace10b
    /// <summary>
    /// This sample shows how to create an empty initial session state,
    /// how to add commands to the session state, and then how to create a
    /// runspace that has only those two commands. A PowerShell object
    /// is used to run the Get-Command cmdlet to show that only two commands
    /// are available.
    /// </summary>
    /// <param name="args">Parameter not used.</param>
    private static void Main(string[] args)
      // Create an empty InitialSessionState and then add two commands.
      InitialSessionState iss = InitialSessionState.Create();

      // Add the Get-Process and Get-Command cmdlets to the session state.
      SessionStateCmdletEntry ssce1 = new SessionStateCmdletEntry(

      SessionStateCmdletEntry ssce2 = new SessionStateCmdletEntry(

      // Create a runspace.
      using (Runspace myRunSpace = RunspaceFactory.CreateRunspace(iss))
        using (PowerShell powershell = PowerShell.Create())
          powershell.Runspace = myRunSpace;

          // Create a pipeline with the Get-Command command.

          Collection<PSObject> results = powershell.Invoke();

          Console.WriteLine("Verb                 Noun");

          // Display each result object.
          foreach (PSObject result in results)
                             "{0,-20} {1}",

        // Close the runspace and release any resources.

      System.Console.WriteLine("Hit any key to exit...");

Making commands private

You can also make a command private, by setting it's System.Management.Automation.Commandinfo.Visibility property to System.Management.Automation.SessionStateEntryVisibility Private. The host application and other commands can call that command, but the user of the application cannot. In the following example, the Get-ChildItem command is private.

defaultSessionState = InitialSessionState.CreateDefault();
commandIndex = GetIndexOfEntry(defaultSessionState.Commands, "get-childitem");
defaultSessionState.Commands[commandIndex].Visibility = SessionStateEntryVisibility.Private;

this.runspace = RunspaceFactory.CreateRunspace(defaultSessionState);

See Also

Creating an InitialSessionState