问使用iTextSharp提取PDF文档的ID

EN

public PdfArray GetId(string FileName)
{
    using (PdfReader pdfReader = new PdfReader(FileName))
    {
        return pdfReader.Trailer.GetAsArray(PdfName.ID);
    }
}

public void PrintId(PdfArray Id)
{
    if (Id != null)
    {
        StringBuilder builder = new StringBuilder();
        builder.Append("ID: ");
        foreach (PdfObject o in Id)
        {
            builder.Append("<");
            foreach (byte b in ((PdfString)o).GetBytes())
                builder.AppendFormat("{0:X}", b);
            builder.Append(">");
        }
        Console.WriteLine(builder.ToString());
    }
}