How to check when a powershell script is done running with Visual Studio

Question

I am running a powershell script from within my app. I can start it and it completes without problem, but how do I check when its done? I need to do other actions, Only once its complete. Here is what I have, for a bit of reference:

Public Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    If requiredEnd = True And requiredPass = True And requiredPath = True And requiredSheet = True And requiredStart = True And requiredUser = True Then
        For I = 0 To 7
            objWriter.WriteLine(aryText(I))
        Next
        objWriter.Close()
        Dim p As Process
        p.Start("powershell", "-ExecutionPolicy ByPass -windowstyle hidden -file .\\Excel.ps1")
        p.WaitForExit()
        If p.HasExited = True Then
            MsgBox("The Process Has Been Completed!")
            Application.Exit()
        End If
    Else
        If requiredEnd = False Or requiredPass = False Or requiredSheet = False Or requiredStart = False Or requiredUser = False Then
            MessageBox.Show("You Have Missing Required Fields!")
        Else
            MessageBox.Show("That Is Not A Valid File!")
        End If
    End If
End Sub

Thanks for the help! Also, I am a beginner at this, so could you do a bit of an explanation on how it works if it isn't super straight forward? Thanks again.

Edit: I realize I forgot the key point: I can close the script, but I need to know if it exited successfully . So a way to check errors, basically.

Answer 1

Why not use a runspace to execute your powershell code in-process, instead of shelling out to an external application? Most of the code you see for this is in C# but you can of course do it in VB.net as well:

    ' create Powershell runspace 
    Dim MyRunSpace As Runspace = RunspaceFactory.CreateRunspace()

    ' open it 
    MyRunSpace.Open()

    ' create a pipeline and feed it the script text 
    Dim MyPipeline As Pipeline = MyRunSpace.CreatePipeline()

    MyPipeline.Commands.AddScript(scriptText)

    ' add an extra command to transform the script output objects into nicely formatted strings 
    ' remove this line to get the actual objects that the script returns. For example, the script 
    ' "Get-Process" returns a collection of System.Diagnostics.Process instances. 
    MyPipeline.Commands.Add("Out-String")

    ' execute the script 
    Dim results As Collection(Of PSObject) = MyPipeline.Invoke()

    ' close the runspace 
    MyRunSpace.Close()

This code is taken from this MSDN blog which has a much more thorough and complete example application, but the basic idea here is to run the code natively in your application and then you can get the output any way you like to test for errors.