I have a setup project with a custom dialog (asks for a server name and a port number). This information is then passed to a custom action DLL.
However, if I have already installed the app and attempt to run the msi again (and choose the Repair option), I do not get the custom dialog displayed and so the custom action is passed empty arguments for the servername and port number.,
Is there anyway on a repair to have the dialog appear If not, can I stop the custom action from running on a repair

Setup project: Custom UI dialogs and reinstall
Luis Alonso Ramos
owen corpening
A repair is a repair, it's not an install of your new MSI. You're attempting to install a product with the same product code guid as an existing product, so it completely ignores your new MSI and just repairs the old one. If you want to reinstall a newer version of the product you have to increase the setup project's version, set RemovePreviousVersions to true etc. See if this helps:
http://www.simple-talk.com/2005/07/18/updates-to-setup-projects/