PowerShell Multiple DynamicParam

I'm attempting to create a function for a script module that verifies the previous parameter has been set before it shows the next parameter.

The parameters I need are Identity, Share and Quota. I always want Identity to show, I don't want Share to show until the Identity has been set and I don't want Quota to show until the Share has been set.

I'm able to easily access $Identity, I'm not able to access $Share from within DynamicParam{}. I stepped through the script using PowerGUI and I was only able to see $Share when I hit Begin{}.

I have a way to workaround this by just showing Share/Quota if Identity is set, but ultimately I would like to learn how to keep adding additional parameters based on the previously set parameter.

A copy of the function is below. personfileutility.exe is just an executable we use to interact with the various systems to provision and gather information on a user.

function New-PersonalFiles
{
    [CmdletBinding()]
    Param
    (
        # Param1 help description
        [Parameter(Mandatory=$true)]
        $Identity
    )

    DynamicParam
        {
            $paramDictionary = new-object -Type System.Management.Automation.RuntimeDefinedParameterDictionary

            if (($Identity -notlike "") -or ($Identity -notlike $null)){
                $attributes = new-object System.Management.Automation.ParameterAttribute
                $attributes.ParameterSetName = "__AllParameterSets"
                $attributes.Mandatory = $true

                $lookup = [xml](\\servername\personalfiles\personfileutility.exe -a $Identity)

                $type = $lookup.User.user_directory.type.type

                if ($type -like "other" -or $type -like "staff") {
                    $arguments = @()
                    $arguments += "\\fileserver\sharename"
                }
                elseif ($type -like "faculty") {
                    $arguments = @()
                    $arguments += "\\fileserver\sharename"
                    $arguments += "\\fileserver\sharename2"

                }
                elseif ($type -like "student") {
                    $arguments = @()
                    $arguments += "\\fileserver2\sharename"
                }

                $ParamOptions = New-Object System.Management.Automation.ValidateSetAttribute -ArgumentList $arguments

                $attributeCollection = new-object -Type System.Collections.ObjectModel.Collection[System.Attribute]
                $attributeCollection.Add($attributes)
                $attributeCollection.Add($ParamOptions)


                $dynParam1 = new-object -Type System.Management.Automation.RuntimeDefinedParameter("Share", [String], $attributeCollection)

                $paramDictionary.Add("Share", $dynParam1)
            }

            if (($Share -like "\\fileserver\*"))
            {
                $attributes2 = new-object System.Management.Automation.ParameterAttribute
                $attributes2.ParameterSetName = "__AllParameterSets"
                $attributes2.Mandatory = $true

                $lookup = [xml](\\servername\personalfiles\personfileutility.exe -a $Identity)

                $type = $lookup.User.user_directory.type.type

                if ($type -like "other" -or $type -like "staff") {
                    $arguments = @()
                    $arguments += "15GB"
                    $arguments += "20GB"
                }
                elseif ($type -like "faculty") {
                    $arguments = @()
                    $arguments += "10GB"
                    $arguments += "15GB"

                }
                elseif ($type -like "student") {
                    $arguments = @()
                    $arguments += "5GB"
                    $arguments += "10GB"
                }

                $ParamOptions2 = New-Object System.Management.Automation.ValidateSetAttribute -ArgumentList $arguments2

                $attributeCollection2 = new-object -Type System.Collections.ObjectModel.Collection[System.Attribute]
                $attributeCollection2.Add($attributes2)
                $attributeCollection2.Add($ParamOptions2)


                $dynParam2 = new-object -Type System.Management.Automation.RuntimeDefinedParameter("Quota", [String], $attributeCollection2)

                $paramDictionary.Add("Quota", $dynParam2)
            }

            return $paramDictionary
        }

    <#
    .Synopsis
       Short description
    .DESCRIPTION
       Long description
    .EXAMPLE
       Example of how to use this cmdlet
    .EXAMPLE
       Another example of how to use this cmdlet
    #>

    Begin
    {
    }
    Process
    {
        \\servername\personalfiles\personfileutility.exe -a $Identity -c -q ((Invoke-Expression $PSBoundParameters.Quota)  / 1KB) -s $Share
    }
    End
    {
    }
}

I'm trying to replicate the "workaround" you're using, but I'm only seeing that I have access to the dynamic parameter Share (not Quota). In order to reproduce your setup, since I don't have access to personfileutility.exe I have commented out two lines and added a third where I hardcode $type to "faculty". For example, in two places I have updated the code to be:

#$lookup = [xml](\\servername\personalfiles\personfileutility.exe -a $Identity)
#$type = $lookup.User.user_directory.type.type
$type = "faculty"

With these changes in place, I can access the Share parameter after I specify an Identity. However, I cannot access the Quota. Do you expect Quota to be available?

If I'm understanding the problem you're asking about, you do not want Share to be accessible until Identity is accessible (which you currently have working). But you in addition, you don't want Quota to be accessible until both Identity and Share are filled out and you don't know how to make that work. Is that correct?

If I'm understanding the problem correctly, I don't believe that PowerShell offers a mechanism to achieve that with Commandlet binding. I think you could make that work by either using a GUI application, or interactively prompting the user for inputs.