Pretty descriptive error code, eh?  Well, I was going to put together an example of what aspnet_merge.exe can do, so the first thing I wanted to do was grab an example application, particularly one that makes use app_code files.  I decided to use the code from BlogEngine.NET.

Yes...I know, I know...the BlogEngine.NET code was never designed to live under a WAP-type model, but surely it can live under that model, right?  Well, uh, not without difficulty.

Step 1: Run aspnet_merge and see what happens
So, I used the Visual Studio 2005 Web Deployment Projects to construct a WDPROJ--an MSBuild project with sweet tasks to run the aspnet_merge utility.  (Note: as far as I can tell, BlogEngine.NET is still a Visual Studio 2005 solution)

At the command line, I typed: msbuild BlogEngine.web_deploy.wdproj



The build started and 54 seconds later...blam!  error MSB6006: "aspnet_merge.exe" exited with code 1.

So, what happened?  Sounds like this error happens when class names collide.  Like so many things, the Web Site project tends to let you get away with bad coding practices like using the same class name for a page's code behind in multiple places--so long as the pages are in separate folders.  Aspnet_compiler will compile separate DLLs so there's never the chance that a single assembly will contain two classes of the same name; however, when aspnet_merge tries to merge all the assemblies into one, the class names will clashes and cryptic errors like "error code 1" will get thrown.

Step 2: Figure out where my problems are and fix them
Unfortunately, the default console logging behavior of MSBuild does not tell me where my errors are, so, after consulting with my handy-dandy MSBuild command line reference, I figure I can do something like this to get more detail on where my errors are occuring:

msbuild /nologo /v:diag BlogEngine.web_deploy.wdproj > msbuild.log

Scrolling up from the bottom of my log, I see this error:

An error occurred when merging assemblies: ILMerge.Merge: ERROR!!: Duplicate type 'widgets_LinkList_edit' found in assembly 'App_Web_nbdnprem'.

Ah-ha!  Multiple classes each named widgets_LinkList_edit.  A quick search for that name reveals that, yes, that class name is used for both the edit.ascx code behind of the LinkList and TextBox widgets.  To fix, I'll go to the TextBox's edit.ascx.cs file and change that class name to widgets_TextBox_edit and to the page declaration in the associated ASCX page and update that, as well.

1...2...3...4 error code 1 issues later and it looks like I have a build!  But do I have a good build?

Step 3: Fire up my BE build to see if it works
Seems like the easiest thing to do is to fire up an instance of the ASP.NET Development Server to host my BE build, so I execute this at the command line:

WebDev.WebServer.EXE /port:8080 /path:"D:\MyTests\BE_Test1\BlogEngine.Web_deploy\Debug_test1" /vpath:"/BE_Test1"

And I get...a Parse Error:



It looks like the page is barfing when it tries to load the PostCalendar user control.  Interestingly, the PostList user control loads fine.  I wonder why?

Looking at the default.aspx markup code, I see that the PostList user control is registered at the top of the page, but the Calendar user control is not.  What gives?



Well, it looks like, as Phil Haack once explained, the controls with the "blog" prefix are registered in the web.config.  Didn't know you could do that.  Pretty cool.

<pages enableSessionState="false" enableViewStateMac="true" enableEventValidation="true">
<controls>
<add namespace="Controls" tagPrefix="blog"/>
</controls>
</pages>

This doesn't fix my problem, though.  ASP.NET Parse Errors are usually an indication that the CLR can't find the referenced class in the assembly.  Well, I know the PostCalendar class is in my single assembly (.NET Reflector told me that), so maybe the CLR is not able to find the assembly itself.  Maybe I can help.  Let's modify the control registration in the web.config with the assembly attribute:

<pages enableSessionState="false" enableViewStateMac="true" enableEventValidation="true">
<controls>
<add namespace="Controls" tagPrefix="blog" assembly="BlogEngine.Web_deploy"/>
</controls>
</pages>

Hey, what do you know?  It worked!  Now, the page loads up just fine.  Note that this last change I made in the web.config in my build folder; if you try to change the original web.config and then run BE from the IDE, you'll get a compiler error.  It seems to me that these kinds of issues can introduce a lot of challenges to development, as you try to account for the fact that the web.config you deploy to a Production server will need to look slightly different than the web.config that you run in your IDE.  I wonder if there are any MSBuild tasks designed to modify the web.config spit out by the build engine?  Scott Guthrie has talked about other important changes that should occur in your web.config before deploying it to Production.  I wonder if anyone has written a MSBuild task to accommodate those changes?

Clicking around in my pre-compiled BE instance, everything seems to work fine; however, I did encounter one show-stopping error that prevents me from doing important administration tasks--like adding a new entry.  At least I know that issue's related to the BE distribution I downloaded, not my build experiment with aspnet_merge.

So, what have I learned?  Doing pre-compilation on complicated Web Site projects can be tricky business--particularly when using aspnet_merge.  I wonder if I should just demo how to migrate a Web Site project to a Web Application project?