PowerShell Reflection

Get-PinvokeMethod.ps1

function Get-NativeMethods
{
    [CmdletBinding()]
    param(
        [switch]$Unsafe
    )
    $Type = 'Microsoft.Win32.NativeMethods'
    if ($Unsafe)
    {
        $Type = 'Microsoft.Win32.UnsafeNativeMethods'
    }
    $SystemAssembly = [AppDomain]::CurrentDomain.GetAssemblies() | Where-Object { $_.GlobalAssemblyCache -And $_.Location.Split('\\')[-1].Equals('System.dll') }
    $SystemAssembly.GetType($Type)
}

function Get-ProcedureAddress
{
    [CmdletBinding()]
    param(
        [OutputType([IntPtr])]
        
        [Parameter(Position = 0, Mandatory = $True)]
        [String]$Module,
            
        [Parameter(Position = 1, Mandatory = $True)]
        [String]$Procedure
    )

    $UnsafeNativeMethods = Get-NativeMethods -Unsafe
    $ModuleHandle = $UnsafeNativeMethods::GetModuleHandle($Module)
    $tmpPtr = New-Object IntPtr
    $HandleRef = New-Object System.Runtime.InteropServices.HandleRef($tmpPtr, $ModuleHandle)

    # Return the address of the function
    Write-Output $UnsafeNativeMethods::GetProcAddress([System.Runtime.InteropServices.HandleRef]$HandleRef, $Procedure)
}

function Get-DelegateType
{
    param(
        [OutputType([Type])]
            
        [Parameter(Position = 0)]
        [Type[]]$Parameters = (New-Object Type[](0)),
            
        [Parameter(Position = 1)]
        [Type]$ReturnType = [Void]
    )

    $Domain = [AppDomain]::CurrentDomain
    $DynAssembly = New-Object System.Reflection.AssemblyName('ReflectedDelegate')
    $AssemblyBuilder = $Domain.DefineDynamicAssembly($DynAssembly, [System.Reflection.Emit.AssemblyBuilderAccess]::Run)
    $ModuleBuilder = $AssemblyBuilder.DefineDynamicModule('InMemoryModule', $false)
    $TypeBuilder = $ModuleBuilder.DefineType('MyDelegateType', 'Class, Public, Sealed, AnsiClass, AutoClass', [System.MulticastDelegate])
    $ConstructorBuilder = $TypeBuilder.DefineConstructor('RTSpecialName, HideBySig, Public', [System.Reflection.CallingConventions]::Standard, $Parameters)
    $ConstructorBuilder.SetImplementationFlags('Runtime, Managed')
    $MethodBuilder = $TypeBuilder.DefineMethod('Invoke', 'Public, HideBySig, NewSlot, Virtual', $ReturnType, $Parameters)
    $MethodBuilder.SetImplementationFlags('Runtime, Managed')
        
    Write-Output $TypeBuilder.CreateType()
}

function Get-PinvokeMethod
{
    [CmdletBinding()]
    param(
        $Module,
        $Method,
        $Parameters,
        $ReturnType
    )
    $MethodAddr = Get-ProcedureAddress -Module $Module -Procedure $Method
    $MethodDelegate = Get-DelegateType -Parameters $Parameters -ReturnType $ReturnType
    [System.Runtime.InteropServices.Marshal]::GetDelegateForFunctionPointer($MethodAddr, $MethodDelegate)
}

function ConvertTo-Enum
{
    [CmdletBinding()]
    param(
        [string]$Name,
        [Parameter(ValueFromPipeline = $true)]
        [hashtable]$Hashtable
    )
    $Domain = [AppDomain]::CurrentDomain
    $DynamicAssembly = New-Object System.Reflection.AssemblyName('DynamicAssembly')
    $AssemblyBuilder = $Domain.DefineDynamicAssembly($DynamicAssembly, [System.Reflection.Emit.AssemblyBuilderAccess]::Run)
    $ModuleBuilder = $AssemblyBuilder.DefineDynamicModule('DynamicModule', $false)
    $ConstructorInfo = [System.Runtime.InteropServices.MarshalAsAttribute].GetConstructors()[0]

    $TypeBuilder = $ModuleBuilder.DefineEnum($Name, 'Public', [UInt16])
    ForEach ($Key in $Hashtable.Keys)
    {
        Write-Verbose "Attempting to add $Key = $($Hashtable[$Key])"
        $TypeBuilder.DefineLiteral($Key, $Hashtable[$Key]) | Out-Null
    }
    $TypeBuilder.CreateType()
}

$NativeMethods = Get-NativeMethods
$UnsafeNativeMethods = Get-NativeMethods -Unsafe
$ShowWindowAsync = Get-PinvokeMethod -Module user32.dll -Method ShowWindowAsync -Parameters IntPtr, Int32 -ReturnType Bool
$VirtualAlloc = Get-PinvokeMethod -Module kernel32.dll -Method VirtualAlloc -Parameters IntPtr, UInt32, UInt32, UInt32 -ReturnType IntPtr

$MachineType = @{
    Native = [UInt16]0
    I386 = [UInt16]0x014c
    Itanium = [UInt16]0x0200
    x64 = [UInt16]0x8664
} | ConvertTo-Enum -Name MachineType -Verbose