安装前运行自定义操作 - Visual Studio 安装程序

Question

I am working on a project where I need to run an action before installing a new version, this action is to check if there a product already installed and to uninstall it. I tried to add custom action in visual studio installer but I can't add a DLL file from the outside of the project so the action won't run before the installation. My application is a Microsoft office addin so that why I used visual installer because it is very simply and straightforward. Is there any another solution?

Note : Changing product code and set DetectNewerVersion to true didn't work, 
       now I have two same product in Program and Features

Answer 1

Here you can find InstallExecuteSequence numbers . You just should put yours custom action in right place, for example you can set Sequence=750 - it will be run before CostInitialize.

Also here's video tutorial how to use orca.exe. It's amazing app to check and debug your msi. In your case you can check is your CustomAction in right place or you should change number, or even your custom action isn't working.

And about "I tried to add custom action in visual studio installer but I can't add a DLL file from the outside of the project so the action won't run before the installation". I can't get what do you mean, but seems that you can't add dll with custom actions. Here's tutorial about it .