Very Technical Question/Problem

bhd8ball

Is it possible to create classes/methods 'on the fly'?? I have business rules that change. I want to create a way for users to create new methods (and new classes) or replace the 'code' in existing methods. All of these business rules would exist on the server. Ergo the classes would exist on the web server. Can the compiler be invoked from a method on the server? Or for that matter create a listener on the server to take these new classes/changed classes and compile them and get them in the classpath (or the C# equivalent of a classpath). Anybody know? Or am I chasing a car I'll never catch? Thanks John

5 Replies

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ssswamii23y ago
JScript .Net has a built in method called 'eval' that will evaluate and execute JScript.Net code on the fly. Because JScript.Net has access to the same .Net Framework class lib that C# does, this may be a good option if you're just looking to execute or evaluate code. If you're trying to build methods and new class types, on the other hand, Reflection and AssemblyBuilder would be a better option.
bhd8ball23y ago
Thanks, I'll look these up. These are business rules (policies) that change often. Currently, these rules are in either stored procedures or the actual SQL is specified and then put in a table. The user actually develops the rules and saves them, the system then executes them according to other rules. Putting them in stored procedures works, of course, but is not as OO as we would want them. HOWEVER, your suggestion of manually compiling them, periodically and then NOT compiling them unless they change is a good one... The code must be generated from the persistant storage (table), creating the byte code. (JAR?) files. Then executed at runtime. If there were any changed (or new) checks they could be dynamically compiled... That's what they call one of them thar' elee-gant solutions? Thanks, again
dip_2004_0523y ago
Here are some articles for dynamic code compilation: http://www.csharpfriends.com/Articles/getArticle.aspx?articleID=118 http://www.codeproject.com/dotnet/dynacodgen.asp You can use a FileSystemWatcher to monitor your source code directory and trigger dynamic compilation when your specific conditions are met. If your Business rules are changing, but your interfaces are defined and constant, you can probably consider using the same component via versioning. If you are doing the coding manually (as against dynamic code generation)I would still recommend manual compilation and updates... - dip
bhd8ball23y ago
Thanks, will look into that area.. Thanks...
james23y ago
John, What you're wanting to do is certainly possible. Take a look at the .Net Component called the Managed C# Compiler. You can add it as a reference to your project. That namespace will allow you to do runtime compiling of assemblies. Granted, I have not worked with this myself, but I have read of others doing it through this method. good luck, -James