Bing found these results
InstallShield Custom Action Reference - Revenera
windows installer - InstallShield CustomAction : How to load …
Using Custom Actions
DLL Custom Actions - Revenera
Calling C# Dll CustomAction - Community
Call a Function in a DLL - Community
Troubleshooting Failures Of DLL Custom Actions - Community
InstallShield: Walk-through of Custom Actions and Sequences
InstallShield - how to write custom action functions - Stack Overflow
installshield - MSI DLL Custom Actions is not working well in ...