I am upgrading an older web app of ours as I referenced in my last blog post. This was originally a straight html app with no dynamic content at all. I created a .Net ASPX web app out of it and used LINQ to quickly and easily create a survey form that our users could fill out. It worked great on my machine.
Unfortunately the happy ending got derailed when I deployed it to our web server. Our web server is an ancient Windows 2000 server box with IIS 5. this is because it’s where all our main apps our housed, everything works and there is great fear in changing it. <sigh>
So, I either had to figure out how to get my .Net 3.5 app running on IIS5 with .Net 2 or I had to abandon LINQ and go back to data readers (yuck!). I first tried to install .Net 3.5 on the web server but quickly found out that it requires Windows XP or Server 2003 as a minimum. OK, so that’s ruled out.
I knew that the asp.net framework has always been 2.0 (until the new release of 4.0 that is) and .Net 3.0 and 3.5 just added extra features on top of 2.0 but never changed the underlying base classes. So you can easily use .Net 3.5 apps on a .Net 2.0 web server. In fact, this has caused a lot of confusion because there simply is no 3.0 or 3.5 selection in IIS for the .Net framework.
I knew if I could just reference the required .Net 3.5 dlls then this shoudl work. Doing a quick search on Google lead me to this great article. I was wondering if something like this was possible and, sure enough, it pointed me in the right direction.
Here is what I did and it worked like a charm.
I first set my build target for the web app in Visual Studio 2008 to .Net 2.0. This caused VS 2008 to instantly remove any non-.Net 3.5 compatible references such as LINQ. I did a build and received numerous errors, most pertaining to my code that made use of LINQ.
I copied the System.core and Linq.Data DLLs into my web app’s bin folder and referenced them. After another attempt to build the solution the LINQ errors went away but it still didn’t understand my lambda expressions or my auto-properties. This makes perfect sense. These are compiler features and not referenced code. Since, by default, asp.net compiles on the server it had better understand these. I could change the autoproperties back to normal properties but there is no lambda equivalent for .Net 2.0.
So, I created a new project and moved all LINQ code into it and had it target .Net 3.5. Having my data access classes in a separate project felt much cleaner and probably would having been an eventual refactoring later. I removed this code from the web app and created a reference to the new project.
Ran a build and received the welcome success message.
I then deployed the web app to the web server. Upon opening one of the new pages, which runs a LINQ query to obtain some data to populate a drop down list, I received the following error:
Could not load type ‘System.ComponentModel.INotifyPropertyChanging’ from assembly ‘System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’
After some googling it turns out that INotifyPropertyChanging wasn’t introduced until .Net 2.0 SP1. Sure enough, our web server had 2.0 but no service packs.
I installed .Net 2.0 SP2 and everything worked great!
I am in the process of redesigning our entire department’s website and that is all built on MVC and several other current technologies. I have another web server that is running 2003 for that. I might miss out on some of the newer IIS 7 features but .Net 4 runs on it just fine so at least this is a major step forward.
Take care!