Anders Hesselbom

Visual Basic/PowerShell interaction

2010-12-18

Through the .NET Framework, Visual Basic can talk to PowerShell. If PowerShell is installed, you can add a reference to an assembly named System.Management.Automation. You will have to browse for it, and you will find it here:

C:\Program Files\Reference Assemblies\Microsoft\WindowsPowerShell\v1.0

Also, scripting needs to be activated in PowerShell.

A RunSpace is a context where PowerShell scripts run. Any variables that are set in one runspace, can be read from that same runspace, but not any other runspace. Before the opening Using, I will create a variable (Result) that will hold the response from PowerShell.

Dim Result As _
   System.Collections.ObjectModel.Collection(Of System.Management.Automation.PSObject)

 Using R As System.Management.Automation.Runspaces.Runspace = _
   System.Management.Automation.Runspaces.RunspaceFactory.CreateRunspace()

Next, you open the runspace and create a pipeline.

R.Open()
Dim P As System.Management.Automation.Runspaces.Pipeline = R.CreatePipeline()

The pipeline has a Commands collection where you add your commands or complete scripts. These two lines will create two output objects.

P.Commands.Add("C:\test.ps1")

When you’re done, you can execute the script using the Invoke function of the pipeline object, and close your runspace. The response is saved in the Result variable I created earlier.

Result = P.Invoke()
R.Close()
End Using

For Each Res As System.Management.Automation.PSObject In Result
   MessageBox.Show(Res.ToString())
Next

The content of my script file, test.ps1, is:

Write-Output "Hello!"
$x = 10 + 3
Write-Output $x

The output of course will be one message box saying Hello! and another saying 13.

Categories: PowerShell

Tags: PowerShell