Would a custom interface get you out of the weeds? Then just require a parameterless ctor that initializes fields to benign values and call the interface .Init/Create etc.
BTW, this wouldn't be an Object/Relational mapping layer would it? Jim > -----Original Message----- > From: Shawn Wildermuth [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, May 07, 2002 10:24 AM > To: [EMAIL PROTECTED] > Subject: [DOTNET] Confusion about the Type system... > > > Please help me understand this stuff. I am missing something > important... If anyone knows of a good reference/description of the > type system, I'd really appreciate a link. > > Here is my problem: > > I have a system where I have a base class (called Profile) that knows > how to store itself in the database. It stores its data in > the database > and its Assembly Qualified Type Name. At runtime I am reading the > Assembly Qualified Type Name and using Activator.CreateInstance to > create the object in memory. I use this system because derived types > may not be located in an assembly that I have access to at > compile-time. > This works fine except that I need to require a certain type of > constructor to be available to know how to construct the > objects (there > are certain data requirements that necessitate the need for a certain > style of constructor). So I would like to do one of two > things (neither > of which I can get to work yet): > > 1. Specify in my base class that a constructor style is required (like > marking it abstract, but C# doesn't support this of course) > .or. > 2. Create objects of the Type of my base class and at runtime, up-cast > them to the new type. > > The nature of these objects is that the base class holds data > structures > that actually hold all the data for derived classes so I don't need to > worry so much about an up-casting needing more memory allocated (since > in the usual case the derived class may be larger in memory than the > base class). I like option #1 as it is a lot more clean, but I just > hate the idea that I can only assert this at runtime. If I could get > derived classes to get a compiler error or warning if they didn't > implement the required constructor, I'd be all set. > > Ideas? > > Thanks, > > Shawn Wildermuth > [EMAIL PROTECTED] > http://adoguy.com > http://shawnwildermuth.com > > "...for the programmer, as for the chef, the urgency of the patron may > govern the scheduled completion of the task, but it cannot govern the > actual completion. An omelette, promised in two minutes, may appear to > be progressing nicely. But when it has not set in two minutes, the > customer has two choices--wait or eat it raw. Software customers have > had the same choices. The cook has another choice; he can turn up the > heat. The result is often an omelette nothing can save--burned in one > part, raw in another.... " - Brooks, The Mythical Man-Month. > > You can read messages from the DOTNET archive, unsubscribe > from DOTNET, or > subscribe to other DevelopMentor lists at http://discuss.develop.com. > You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
