PdfDocumentProperties Class
该类，用来显示载入的pdf文件的属性，包括：
| Name | Description | |
|---|---|---|
 |
Application | Indicates the application that generated the document. |
|
Author | Indicates a document's author. |
|
CreationDate | Specifies the date of the PDF file creation. |
|
FileLocation | Indicates the physical location of a document. |
|
FileName | Indicates a document's file name. |
|
FilePath | Indicates a path to the folder that contains the document file. |
|
FileSize | Indicates the physical size of the document file. |
|
Keywords | Indicates the keywords that describe the primary topics covered in a document. |
|
ModificationDate | Specifies the date of the PDF file's last modification. |
|
Producer | Indicates an application that produces a PDF. |
|
Subject | Indicates the primary subject of a document. |
|
Title | Indicates the title of a document. |
|
Version | Specifies the PDF version of a document. |