Partial application updates in ClickOnce using Visual Studio build

Question

I am using VS2008 to publish my application files using ClickOnce. I read somewhere that ClickOnce intelligently does only partial updates; meaning it only downloads files from the network share if the file has changed in subsequent updates. However, this wasn't working for me. So I did some research and stumbled upon this MSDN article - http://msdn.microsoft.com/en-us/library/ms404267.aspx. It says that if we build using VS, it doesn't perform the partial updates. Can anyone tell me why this is the case? If so, is there a way to atleast let the referenced dlls to be downloaded only for the first time. I am using Microsoft Practices Enterprise Library and some 3rd party controls (with huge Theme files).

Thanks, Uniball

Answer 1

Partial updates work fine in ClickOnce even when building in VS. However, if you have a solution made up of a few projects (eg a couple of class library projects and an executable) then any time you rebuild all the projects the timestamp on the assembly files will change, even if the code hasn't. Since ClickOnce really only looks at the timestamps to decide whether a file needs updating, it'll pull down the (unchanged) assemblies as new files when the user updates.

The workaround is to pull any dependent projects out of your executable's solution file and build them separately. That means that any assemblies whose code doesn't change very often will only get pulled down to the client once. If you need to change the assembly, you simply open its solution and make the change, then reopen your executable's solution and rebuild that. The next ClickOnce update will pull down both the exe and the changed assembly.

Hope that's clear enough!