File type associations

I hope someone can help here. I need to display, in a DataGridView, the file type icon associated with a file. All I have is the filename from a database (eg: "text.doc"). I want to get the Icon without having to create a document. These documents are not saved on the harddrive, but in a byte field in the DB as well. When a user wants to view the file, it is dynamically created, and released depending on the actions of the user. Does anyone know how to get the associated Icon without the file actually existing?