Extract XLSX Metadata via .NET

// load the XLSX with an instance of Workbook
var book = new Aspose.Cells.Workbook("template.xlsx");
// iterate over the BuiltInDocumentProperties collection
foreach (Aspose.Cells.Properties.DocumentProperty property in book.Worksheets.BuiltInDocumentProperties)
{
    Console.WriteLine($"\tType:\t{property.Type}");

    // Some properties may store multiple values
    if (property.Value is Array)
    {
        foreach (object value in property.Value as Array)
            Console.WriteLine($"\tValue:\t\"{value}\"");
    }
    else
    {
        Console.WriteLine($"\tValue:\t\"{property.Value}\"");
    }
}