Null items coming in library items results

I am trying to get items in specific library using

Get-SPWeb http://sitecollection/sites/site/subsite |
    Select -ExpandProperty Lists |
    Where { $_.GetType().Name -eq "SPDocumentLibrary" -and
            $_.Name -like "SitePages" } |
    Select -ExpandProperty Items |
    Select Name, {$_.File.Length}, url

However, I am getting null, but there are items in the library. I have tried -eq also, but no luck