Web Deployment Projects, Web Application Projects and aspnet_merge.exe

Submitted on May 09, 2007, 2:37 a.m.

aspnet_merge.exe exited with code 1 - read on...

There are a few good articles around that describe the differences between the default Web project in VS2005, and Web Application Projects (which are included with SP1 now). Having come from custom scripts using XCOPY in VS 2003 - I was comfortable with the Web Application Project model - knowing that the site would be compiled into a single DLL which along with all the required files to run the site - could just be copied/XCOPYd/FTPd into production.

I also think the loose directory structure and compilation options of the standard Web Project in VS2005 are pretty cool too. That said for a lot of Web applications - I think the Web Application Project makes a lot of sense.

Rick Strahl has written a pretty good summary of the issues and differences between the default Web Project and Web Application Project formats - at Web Application Projects and Web Deployment Projects are here 

We recently switched back to a Web Application Project on one project - but wanted to keep the Web Deployment Project - since the compiler options, pre and post build command options (in the source project file) were a convenient place to perform configuration specific tasks in a build.

For one site in particular we wanted to be able to publish new binaries quickly if needed and so the Web Deployment options were set to 'Merge all outputs to a single assembly', and 'Treat as libaray component'.

I chose the default namespace for the Web Application Project as the assembly name to merge to in the Web Deployment Project.

And at that point I was stuck - the build failed with am '"aspnet_merge.exe" exited with code 1' failure message.

I enabled Detailed MSBuild messages in the Output window - (Tools, Options, Projects and Solutions, Build and Run - bottom combo box) and saw the following message the next time I tried to build.

The target assembly 'DCL.MG.Web' lists itself as an external reference.

After some experimenting - I told the Web Deployment Project to build to an assembly with a different name - in this case "DCL.MG.Website" - and I discovered two assemblies in the output directory. One called DCL.MG.Web.dll (from my Web Application Project) and one called DCL.MG.Website.dll which the Web Deployment Project had created.

Using IL DASM - I could see that the DCL.MG.Website assembly had only two classes in it - an ApplicationBrowserCapibilitiesFactory and global_asax. The rest of the site had compiled into the DCL.MG.Web assembly fine.

I can live with this extra assembly - it's small and uploads fine with the other binaries when we do an update. I'm just a little curious as to why this is happening - why we're not getting a single assembly, and whether anyone else has discovered this as well.