Powershell script works but not in vb.net code - vb.net

Question

I need to run a powershell script from vb.net. I wrote it and tried it in powershell ISE and the powershell console and it's working properly.
But when I try to use it in my vb.net code, nothing happens.
The script put into text file citrix session from some user.
here is my powershell script :
$username = 'domain\myusername'
$password = 'mypassword'
$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
$credential = New-Object System.Management.Automation.PSCredential $username, $securePassword
Start-Process C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -Credential $credential -NoNewWindow -ArgumentList "add-pssnapin citrix*`nGet-BrokerSession -AdminAddress 'ipadresshere' | Out-File -FilePath C:\inetpub\wwwroot\gestusers\ajax\data\arrays.txt"
and here's my vb.net code :
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()
' convert the script result into a single string
Dim MyStringBuilder As New StringBuilder()
For Each obj As PSObject In results
MyStringBuilder.AppendLine(obj.ToString())
Next
' return the results of the script that has
' now been converted to text
Return MyStringBuilder.ToString()
When I try to use a smaller script like :
$test = "blablabla"
$test | Out-File -filepath "C:\inetpub\wwwroot\gestusers\ajax\data\arrays.txt"
it works so I don't really understand why the first script is not working .. if you have some suggestion I would be thankful

Answer 1

I finaly found a solution to my problem.
I am running my web app on a IIS server and when I was launching my script it was the default user "IIS default/application_pool" which was lauching it although I specified a specific user to run it, it was like my script doesn't work.
So I choosed to go in my IIS server params and I just made an other app_pool with my specific user. I put my app under this pool and now it works perfectly.
Here's how to make a specific pool on IIS Server : https://www.developer.com/net/asp/article.php/2245511/IIS-and-ASPNET-The-Application-Pool.htm
cya