Question

I’m writing an installer file in WiX with a custom action defined in a DLL. The custom action runs on uninstall, and if it fails, I want it to stop the uninstall process and rollback. The action doesn’t affect the system, so I am able to call it before InstallInitialize, so it shouldn’t have other changes to undo.

I was told that if I defined a property for the custom action, I could then use condition to halt the uninstallation process, as follows:

<SetProperty Id="CA_mine" 
             Value="No" Sequence="execute" 
             Before="CA_mine">
  Installed AND remove=ALL
</SetProperty> 
<CustomAction Id="CA_mine" BinaryKey="BIN_mine" DllEntry="mine" Execute="immediate"/>
<InstallExecuteSequence>
  <Custom Action="CA_mine"
          Before="InstallInitialize">
    Installed AND remove=ALL      
  </Custom>
</InstallExecuteSequence>

<Condition>
  NOT (Installed AND remove=ALL)  OR [CA_mine] = "No"
</Condition>

Where mine sets the property CA_mine to be “Yes” if I want the uninstall to stop.

Would this even work? When is the condition tag evaluated? Is there a simpler way to accomplish my goal here (rolling back uninstallation when mine fails)?

Answer 1

The Condition element, when nested under the Product element, refers to the LaunchConditions table.

Your custom action needs to be scheduled before the LaunchConditions action so that the property is set and available for evaluation. Think of it as an extension to the AppSearch action.