Gets exported types from one or more assemblies.

Get-ExportedTypes.ps1

[CmdletBinding(DefaultParameterSetName = 'Path')]
param (
    [Parameter(ParameterSetName = 'Path', Position = 0, Mandatory = $true)]
    [string[]] $Path,

    [Parameter(ParameterSetName = 'LiteralPath', Mandatory = $true, ValueFromPipelineByPropertyName = $true)]
    [Alias('PSPath')]
    [string[]] $LiteralPath
)

if ($PSCmdlet.ParameterSetName -eq 'Path') {
    $LiteralPath = $Path | Resolve-Path
}

foreach ($p in $LiteralPath) {
    $file = [System.IO.File]::OpenRead($p)
    try {
        $pe = [System.Reflection.PortableExecutable.PEReader]::new($file)
        try {
            $meta = [System.Reflection.Metadata.PEReaderExtensions]::GetMetadataReader($pe)
            foreach ($typeHandle in $meta.TypeDefinitions) {
                $type = $meta.GetTypeDefinition($typeHandle)
                $attr = $type.Attributes
                if ($attr -band 'Public' -and !$type.IsNested) {
                    [pscustomobject]@{
                        Name = $meta.GetString($type.Name)
                        Namespace = $meta.GetString($type.Namespace)
                    }
                }
            }
        } finally {
            $pe.Dispose()
        }
    } finally {
        $file.Dispose()
    }
}

<#
.SYNOPSIS
Gets exported types from one or more assemblies.

.DESCRIPTION
Gets all the public, non-nested types in given assemblies. No assembly resolution is necessary, so dependencies do not need to be loaded.

.PARAMETER Path
One or more assembly file paths. Wildcards are supported.

.PARAMETER LiteralPath
One or more resolved assembly file paths. Wildcards are not supported.

.EXAMPLE
Get-ExportedTypes.ps1 Assembly.dll | Select-Object Namespace -Unique

Gets all namespaces defined by types in the assembly.
#>