Long time ago, I made an application near to your requirements. The main design was: An abstract base Shape class having some methods like a void Render(Graphics) and a method for hit testing,bool HitTest(Point). Shape classes for custom shapes that are needed on each layer; shapes like point, line, icon, path, etc that inherit from abstract Shape class. Each derived shape has its own properties and overrides Render method and renders itself on the graphics object; also overrides HitTest method to check if it contains a point. A Layer class that contains a List of Shapes and a void Render(Graphics) and calls render method of each shape. (You can restrict each layer to specific types of shapes, you can implement z-order management for shapes, etc) A Map class having and Image and a List<Shapes> and Save and Load to/from file. (You can handle Active layer and active shape easily.) A custom control that has a Map property. This control is responsible for rendering layers and handling user mouse interaction and update layers. This control overrides OnPaint and mouse events and enables double buffering. Hope this idea helps you.

Web Services are really a great route for this kind of thing. You could also look into ProtoBuf[^] if you really care about latency (XML can add a few nanoseconds here and there). Finally, IKVM[^] lets you run Java code directly on the .Net framework (you might want to look at ikvmc[^] specifically). He who asks a question is a fool for five minutes. He who does not ask a question remains a fool forever. [Chinese Proverb] Jonathan C Dickinson (C# Software Engineer)

Thank you very much, it seems really interesting. Nevertheless, if anyone has any other suggestion, I'm all ears. Thank you again.

Thanks for your help to both!

One thing to remember about T-SQL is that by default if you have a null in an expression the expression is null. Thus COALESCE(@PKCols + ' and', ' on') would return ' on' if @PKCols is null as NULL + ' and' returns NULL. Also NULL cannot be compared to another NULL as in WHERE NULL = NULL because this returns NULL not true or false. This gets me on occasion. Besides the COALESCE function there is ISNULL, used like WHERE ISNULL(@PKCols, '') <> '' Hope this is more helpful than confusing.

As I said I had not used it. I guess that would make sence but I figured it has some simple reader/writers. When I was doing work with it we saw that CP project and learned from it. We then worked with our CAD group to understand what type of files they were generating etc. and built our own reader from that. We did not have to do any writting. As I said, DXF are just text files. They can however get very complex depending on the layers. If your users need a lot of layers with different rules you likely will need to purchase something. If not I would just play with it and make a small library that you can keep extending upon. Good luck :) Computers have been intelligent for a long time now. It just so happens that the program writers are about as effective as a room full of monkeys trying to crank out a copy of Hamlet.