Question

I have a Windows.Forms client that is packaged as MSI by using a Visual Studio Deployment Project.

My app.config has some configuration properties whose values must be replaced by the correct ones depending on the environment I want to deploy the client into.

For instance, my client do connect to a set of COM+ services that are behind a WCF facade, so I have some URLs in the configuration file that vary depending on the environment (development, integration, etc etc).

In such way one can find in the application config line like this:

<add ServiceName="MyService" ServiceEndpoint="$(WS_URL)/MyService.svc" MaxMessageSize="xxxxxx"></add>

Well, the thing is that I need to execute a batch file (.bat) to load some variables and then replace the variables in the app.config, but, I need to do the replacements in the application configuration file that is being packaged in the MSI, and not perform the replacement in the “original” configuration file that is in the client project.

In fact what I would need is just to get the path, of the application configuration file, that VS is about to package, and pass the file-path to my script so that it does the replacements.

NOTE: In the above sample line $(WS_URL) is the variable that must be replaced by its correct value depending on the deployment environment configuration.

Answer 1

Finally I have the solution that fit our needs. My need was mainly to just have one unique configuration file for the Windows.Forms client and being able to replace some property values in it, just before the file is packaged in the MSI.

I thought the binaries that are packaged within the MSI were taken from the project(s) output dir., but they are not, so I couldn’t use that location to execute our “variable replacer” script and get the final App.config file ready to be packaged.

We a have a .bat file, one for each kind of environment configuration, in which we centralize the configuration properties applying for Windows.Forms, Web-Applications, COM+ Serviced Components, so I was disgusted with the idea of replicating the configuration file of the client, because my aim is also to reduce the number of configuration files, to reduce the risk of making a mistake, while keeping the process of creating/maintaining build environments easy.

I couldn’t find any doc to tell me how could I get the path, of the temporal folder or whatever, where the files are, just before the MSI is being packaged. If I would have access to it, then I would have executed our “variable replacer” script pointing to that directory and problem solved.

My workaround was to place a customized pre-build event, so that the I copy the “template” App.config to the project directory, and once it is there, I run the script to replace the property values.

Now, every time the deployment project is built, we are sure it contains a valid configuration file.

Just FYI, here is how the pre-build event looks like:

XCOPY /Y $(ProjectDir)config\*.* $(ProjectDir)
CALL ..\ScriptsCentral\do_apply_config.bat $(ProjectDir)App.config etc
EXIT 0

NOTE: I had to put the EXIT 0 explicitly because we build all the projects with msbuild and devenv.com and I got the build process stopped in the part where it executes the build event.

(thanks @ChristopherPainter for your time and comments. +1 for your proposal)