how to add logic to msi installer

I have a 开发者_JAVA技巧Setup Project in Visual Studio 2010 which creates a .msi installer. I am wondering if it is possible to add some logic to check some conditions. e.g if there is my software installed yet.

Thanks,

This is done through installer properties. You can set them and check them against values. They are just like variables in code.

However, Visual Studio is limited when it comes to custom installation logic. If you don't figure out how to do what you need, give us more details.

As a side note, launching the installer for an already installed product makes it go into maintenance mode (Modify, Repair and Remove options). So you don't need to check if your application is already installed.

You need to add installer class to one of your library or assembly. In Visual Studio, attach installer events to custom action. See how http://www.simple-talk.com/dotnet/visual-studio/visual-studio-setup---projects-and-custom-actions/ or here http://msdn.microsoft.com/en-us/library/d9k65z2d.aspx