strange behavior when selecting multiple values in GridView

Question

&nbsp;I was writing a script to export Hyper-V VM, the script is basically meant to be run from CLI or scheduled-tasks. but I like to make my script also able to be used interactively.&nbsp;In Screencast GIF above, if no VMs have been supplied through CLI, a GridView is shown with names of available VMs. Multiple values (VMs) can be selected in the GridView. The Code for displaying GridView and reading the selection is highlighted in screencast.&nbsp;If I start the script through Powershell-ISE start button (F5), then the script works as expected, if multiple values are selected, values are then stored as array.&nbsp;If the script starts through commandline, and multiple values are selected in GridView, all the selected values are stored as a string, which is not the desired behavior!&nbsp;Why is it so and how to resolve it to get the expected result?&nbsp;OS is Windows 10 Pro&nbsp;22H2

lainrobertson · Answer

Shehzad&nbsp;&nbsp;I still cannot make Out-GridView do what you suspect it of doing - which is actually a good thing, so I've taken a look at your script and provided an alternative below.&nbsp;It's not identical but similar and maybe gives you some ideas for your own script.&nbsp;The version I'd dropped below:&nbsp;Can work locally on a hypervisor or remotely (so long as you have the Hyper-V tools components installed);Leverages the fact that the -Name parameter from the native Export-VM command is actually a string array type, not just a string (so I've skipped the per virtual machine looping altogether, which is more efficient).&nbsp;Anyhow, it's just something else to review given I can't find any issues at all with Out-GridView.&nbsp;&nbsp;&nbsp;[CmdletBinding()]
Param (
  [Parameter()][string[]] $VMName           # Name of the VM to export
  , [Parameter()][string] $Path = "D:\Data\Temp\Forum\Export"       # Path to export VM to
  , [Parameter()][switch] $AppendDate       # Whether to append datetime to export path
  , [Parameter()][string] $ComputerName     # The hypervisor you want to connect to
)

function Export-VirtualMachine
{
    Param (
        [Parameter(Mandatory=$true)][ValidateNotNullOrEmpty()][string[]] $Name  # Name of the VM to export
        , [Parameter()][string] $Path = "D:\Export"                             # Path to export VM to
        , [Parameter()][string] $ComputerName                                   # The hypervisor you want to connect to
    )

try
    {
        if ([string]::IsNullOrWhiteSpace($ComputerName))
        {
            Export-VM -Name $Name -Path $Path;
        }
        else
        {
            Export-VM -ComputerName $ComputerName -Name $Name -Path $Path;
        }
    }
    catch
    {
        throw;
    }
}

#region Set up some variables.
$Err_NoMachines = "No virtual machine names found. Aborting."
$Timestamp = [datetime]::Now.ToString("yyyyMMdd-HHmmss");
$Names = [System.Collections.Generic.List[string]]::new();
#region

try
{
    #region Validate the parameters.
    if ([string]::IsNullOrWhiteSpace($Path))
    {
        # We'd only be in here if someone deliberately passed "-Path $null" into the script. Unlikely but possible.
        throw "-Path cannot be null.";
    }

if ($AppendDate.IsPresent)
    {
        if ($Path.EndsWith("\"))
        {
            $Path = $Path.Substring(0, $Path.Length-1);
        }

$Path += "-$Timestamp";
    }

foreach ($Entry in $VMName)
    {
        if (-not [string]::IsNullOrWhiteSpace($Entry))
        {
            $Names.Add($Entry);
        }
    }
    #endregion

if ($Names.Count -gt 0)
    {
        # Being in this block means we have names passed in from the calling process. We get to play dumb here as it's up to the caller to have ensured the $VMName and $ComputerName parameters are correct.

Export-VirtualMachine -ComputerName $ComputerName -Path $Path -Name $VMName -ErrorAction:Stop;
    }
    else
    {
        # Being in this block means no names were passed in from the calling process.

#region Fetch the virtual machine names from the nominated $ComputerName (or local host if $ComputerName is empty). Note: We're not splitting on commas as it's one name per line, not a character-separated single line.
        $AllNames = [System.Collections.Generic.List[string]]::new();

if (-not [string]::IsNullOrWhiteSpace($ComputerName))
        {
            (Get-VM -ComputerName $ComputerName -ErrorAction:Stop).Name |
                ForEach-Object {
                    $AllNames.Add($_);
                };
        }
        else
        {
            (Get-VM -ErrorAction:Stop).Name |
                ForEach-Object {
                    $AllNames.Add($_);
                };
        }

if (0 -eq $AllNames.Count)
        {
            Write-Warning -Message $Err_NoMachines;
            return;
        }

$AllNames.Sort();
        $AllNames.Insert(0, "All");     # Cram a value of "All" at the start.

# Prompt the user to choose.
        $Names = [string[]] ($AllNames | Out-GridView -OutputMode Multiple);    # Notice here that we're forcing a typecast of a string array ([string[]]). This avoids unwieldly "if..else" checking.

if (0 -eq $Names.Count)
        {
            Write-Warning -Message $Err_NoMachines;
            return;
        }
        elseif ($Names.Contains("All"))
        {
            $AllNames.RemoveAt(0);
            $Names = $AllNames;
        }
        #endregion

if (-not [string]::IsNullOrWhiteSpace(($NewPath = (Read-Host -Prompt "Enter an export path or leave empty to use the default ($Path)"))))
        {
            $Path = $NewPath;
        }

Export-VirtualMachine -ComputerName $ComputerName -Path $Path -Name $Names -ErrorAction:Stop;
    }
}
catch
{
    # We could perform some other actions here, but for this example, we're just going to re-throw the exception up to the caller and let them worry about it.
    throw;
}&nbsp;&nbsp;&nbsp;Edit #1: To include the "All" option handling (which I'd missed in the original.)Edit #2: Correction on line 61 where I'd missed "-not".&nbsp;Cheers,Lain

shehzad · Answer

yes you are right about splitting from Comman, it was either to be semi-colons or comman, but since there are rarely commas in VM-Names, especially in the case where I wanted to use the script. So I went with commas.&nbsp;&nbsp;The script on github is my script, I have posted it this morning myself

lainrobertson · Answer

Shehzad&nbsp;&nbsp;Are you able to post the code down to and including the remote call to the hypervisor?&nbsp;Also, which version of PowerShell are you running within the ISE session? (Type&nbsp;$PSVersionTable in the blue section.)&nbsp;I can't reproduce the behaviour of Output-GridView producing a string when multiple list values have been selected.&nbsp;Cheers,Lain

shehzad · Answer

LainRobertson&nbsp;Thanks for the response, sure, here is the link to complete code on github:&nbsp;https://github.com/fahidsh/hyper-v-exporter/blob/main/vm-exporter.ps1&nbsp;But I think it has to run on a Computer where Hyper-V is installed and probably has a few VMs (can be dummy/empty ones), since it uses the Get-VM command to get the VMs configured.&nbsp;the way I am building my array for the GridView is through Get-VM, in the code&nbsp;# Get All Virtual Machines on the Hyper-V Host
$VirtualMachines = Get-VM

# Add 'All' to the start of array of VM Names
$VirtualMachinesNames = @("All") + $VirtualMachines.Name

# Display the list in Grid
$VMName = $VirtualMachinesNames | Out-GridView -Title "Select VM to export" -OutputMode Multiple

# Print the Selected VM Names
foreach($vm in $VMName){
  Write-Host $vm
}

# Print the number of elements selected
Write-Host $VMName.Count&nbsp;&nbsp;I know if use a static list, it works fine, i.e.&nbsp;# a static list/array
$VirtualMachines = @("VM1", "VM2", "VM3", "VM4")

# Add 'All' to the start of array of VM Names
$VirtualMachinesNames = @("All") + $VirtualMachines

# Display the list in Grid
$VMName = $VirtualMachinesNames | Out-GridView -Title "Select VM to export" -OutputMode Multiple

# Print the Selected VM Names
foreach($vm in $VMName){
  Write-Host $vm
}

# Print the number of elements selected
Write-Host $VMName.Count&nbsp;&nbsp;

harm_veenstra · Answer

You don't need to have Hyper-V installed on the machine, and you need to have the management tools installed. You can do that by running: Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-Management-PowerShell -NoRestart:$trueAfterwards, the Get-VM cmdlet should work, and you can use the -ComputerName parameter to specify a remote host.

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strange behavior when selecting multiple values in GridView

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