The persistency manager serializes a document, which is organized in sections. The persistent document is represented by the NPersistentDocument class, which contains a collection of NPersistentSection instances. Each section is in fact a named object, which must be serialized. The following code will serialize in XML only one path node:

// create a rectangle
rect = new NRectangleShape(10, 10, 20, 20);

// create a new persistent document NPersistentDocument
document = new NPersistentDocument("My document");

// create a new section which will store the rect
document.Sections.Add(new NPersistentSection("Rectangle", rect);

// set the document to the manager
persistencyManager.PersistentDocument = document;

// save the document to a file
persistencyManager.SaveToFile("c:\\temp\\mysavefile.ndx", PersistencyFormat.XML);

// load the same document from the file
persistencyManager.LoadFromFile("c:\\temp\\mysavefile.ndx", PersistencyFormat.XML);

// get the loaded rectangle
NRectangleShape loadedRect = (persistencyManager.PersistentDocument.Sections[0].Object as NRectangleShape);

' create a rectangle
Dim rect As New NRectangleShape(10, 10, 20, 20)

' create a new persistency document NPersistencyDocument
Dim document As New NPersistentDocument("My document")

' create a new section which will store the rect
document.Sections.Add(New NPersistentSection("Rectangle", rect))

' set the document to the manager
persistencyManager.PersistentDocument = document

' save the document to a file
persistencyManager.SaveToFile("c:\\temp\\mysavefile.ndx", PersistencyFormat.XML)

' load the same document from the file
persistencyManager.LoadFromFile("c:\\temp\\mysavefile.ndx", PersistencyFormat.XML)

' get the loaded rectangle
Dim loadedRect as NRectangleShape = (persistencyManager.PersistentDocument.Sections.Item(0).Object as NRectangleShape)

As mentioned the persistency manager supports binary, XML and SOAP serialization. The basic SaveToFile, LoadFromFile, SaveToStream and LoadFromStream methods of the manager request as argument the format which must be used.

In order to dynamically recognize the type of document being loaded from a file the persistency manager assumes that the library and drawing documents are saved in files with the following extensions:

The persistency manager provides several methods, which can facilitate the saving of drawing and library documents to files. These are SaveDocumentToFile , SaveLibraryToFile and SaveDrawingToFile . They all have two overrides - the first one accepts only one argument - the document which must be saved, while the second one also accepts the file name in which the document must be saved. The Save methods which do not have a file name argument show a Save File Dialog. In all save methods the persistency format is determined by the file extension. For example:

// save a drawing document to SOAP
NDrawingDocument drawing = new NDrawingDocument();
persistencyManager.SaveDocumentToFile(drawing, "c:\\temp\\drawing1.nds");

// save a drawing document to user selected file (format is determined by the extension)
persistencyManager.SaveDocumentToFile(drawing);

' save a drawing document to SOAP
Dim drawing As New NDrawingDocument
persistencyManager.SaveDocumentToFile(drawing, "c:\\temp\\drawing1.nds")

' save a drawing document to user selected file (format is determined by the extension)
persistencyManager.SaveDocumentToFile(drawing)

Analogously to document saving the manager provides the following set of methods which can help you load documents from files: LoadDocumentFromFile , LoadLibraryFromFile and LoadDrawingFromFile . The following code loads the drawing saved by the previous example:

// load a drawing from a file
drawing = persistencyManager.LoadDrawingFromFile("c:\\temp\\drawing1.nds");

' load a drawing from a file
drawing = persistencyManager.LoadDrawingFromFile("c:\\temp\\drawing1.nds")

Windows Forms: Extensions - Persistency Manager