Question

In short, I’m just looking for the PowerShell equivalent of how a batch file can call a script with the same parameters…

"%~dpnx0" %*

…where "%~dpnx0" expands to the absolute path of the script and %* is expanded to the list of parameters. Is there an easy way to replicate %*? Or, at least, a way that works?

I have a PowerShell script that uses the System.Data.OleDb namespace to read data from an Excel workbook. Because there is no 64-bit implementation of the Microsoft Jet provider, the script needs to be run from a 32-bit PowerShell session. Rather than simply having the script fail with an error message if it’s run from a 64-bit session, I’d like to have the 64-bit session invoke the script in and retrieve the results from a 32-bit session. I found that this can be done using the Start-Job cmdlet with the -RunAs32 switch, however I’m having trouble providing a value for the -ArgumentList parameter.

I came up with the following to search for whichever script parameters have values and build a command line out of them:

function GetValueText([Object] $value)
{
    [String] $text = if ($value -eq $null) {
        '$null';
    } elseif ($value -is [String]) {
        "'$value'";
    } elseif ($value -is [Array]) {
        '@({0})' -f (($value | ForEach-Object { GetValueText $_ }) -join ', ');
    } else {
        "$value";
    }

    return $text;
}

if ([IntPtr]::Size -gt 4)
{
    [String] $scriptPath = $MyInvocation.MyCommand.Path;
    [String[]] $parameters = @(
        $MyInvocation.MyCommand.Parameters.Keys `
        | ForEach-Object {
            [Object] $parameterValue = Get-Variable -Name $_ -ValueOnly;

            if ($parameterValue -ne $null)
            {
                [String] $parameterValueText = GetValueText $parameterValue;

                '-{0}' -f $_;
                $parameterValueText;
            }
        }
    );
    [Object] $job = Start-Job -FilePath $scriptPath -RunAs32 -ArgumentList $parameters;
    [Object[]] $data = $job | Wait-Job | Receive-Job;

    $data;
}
else
{
    # Retrieve data...
}

When it gets to the Start-Job line it generates an error with message "Cannot convert value "-Argument1" to type "System.Int32[]"". -Argument1 is the script’s first parameter and is of type [Int32[]], so does this mean that -ArgumentList only works with positional and not named parameters?

I’ve also tried simplifying it to…

param(
    [String] $stringArg,
    [Int32] $int32Arg
)

$PSBoundParameters;

if ([IntPtr]::Size -gt 4)
{
    [String] $scriptPath = $MyInvocation.MyCommand.Path;
    [Object] $job = Start-Job -FilePath $scriptPath -RunAs32 -ArgumentList @PSBoundParameters;

    $job | Wait-Job | Receive-Job;
}
else
{
    Get-Date;
}

…but when I run .\Test.ps1 'string' 12345 from a 64-bit session, it displays…

Key                                                         Value
---                                                         -----
stringArg                                                   string
int32Arg                                                    12345
Start-Job : Missing an argument for parameter 'ArgumentList'. Specify a parameter of type 'System.Object[]' and try again.
At X:\Test.ps1:11 char:72
+     [Object] $job = Start-Job -FilePath $scriptPath -RunAs32 -ArgumentList <<<<  @PSBoundParameters;
    + CategoryInfo          : InvalidArgument: (:) [Start-Job], ParameterBindingException
    + FullyQualifiedErrorId : MissingArgument,Microsoft.PowerShell.Commands.StartJobCommand

…so @PSBoundParameters seems to evaluate to $null. I’m not sure why this isn’t working or what else to try.

Answer 1

This is probably going to look a little odd, but:

param(
[String] $stringArg,
[Int32] $int32Arg
)

if ([IntPtr]::Size -gt 4)
{
[String] $scriptPath = $MyInvocation.MyCommand.Path;

$params = @()
$psboundparameters.keys |
  foreach {
      $params += "-$($_)"
      $params +=  $psboundparameters.$_
      }


$sb = [scriptblock]::Create(@"
&'$scriptpath' $params
"@)

[Object] $job = Start-Job -scriptblock $sb -RunAs32 
$job | Wait-Job | Receive-Job;
}
else
{
Get-Date
}