Wix Custom Action – session empty and error on deferred action

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Similar Answers: I want to add some linkes to previous answers on the topic of deferred mode custom actions. There are links to github-samples in these answers – including one sample which uses the DTF class CustomActionData to easily send properties to deferred mode (once you are properly set up):

  • How to hide the value of customactiondata in logs of MSI?

  • Pass ConnectionString to Custom Action in WiX Installer (escape semicolon)

UPDATE: It is late, I didn’t see this on first sight, but only immediate mode custom actions can be run from the setup GUI. Make a new, immediate mode custom action to set a value to your PUBLIC property CONN, and then set the value of CONN via a type 51 custom action to be assigned to the Id of the deferred mode custom action – as described below.

SecureCustomProperties: Add the property you specify to SecureCustomProperties by setting the Secure=”yes” attribute:

<Property Id="MYPROPERTY" Secure="yes">Send this text to deferred mode</Property>

Name Match: the property name you assign the value to must match the deferred mode custom action Id. Looks OK in your source.

More Technical: the Property attribute's value of the type 51 action must be identical to the Id of the custom action that is consuming CustomActionData:

<!-- Declare property with value -->
<Property Id="MYPROPERTY" Secure="yes">Send this text to deferred mode</Property>

<!-- Type 51 CA: Send value of MYPROPERTY to the deferred mode CA named MyAction -->
<CustomAction Id="MyAction.SetProperty" Return="check" Property="MyAction" Value="[MYPROPERTY]" />

<!-- The deferred mode custom action -->
<CustomAction Id="MyAction" Return="check" Execute="deferred" BinaryKey="CAs" DllEntry="MyAction" />

<!-- ... -->

<!-- Inserting the CAs in sequence -->
<InstallExecuteSequence>
    <Custom Action="MyAction.SetProperty" After="InstallInitialize" />
    <Custom Action="MyAction" Before="InstallFinalize" />
</InstallExecuteSequence>

Here are some resources:

  • How to pass CustomActionData to a CustomAction using WiX?
  • https://www.firegiant.com/wix/tutorial/events-and-actions/at-a-later-stage/
  • How to access installer properties from deferred custom actions
  • Accessing or Setting Windows Installer Properties Through Deferred, Commit, and Rollback Custom Actions
  • Getting CustomActionData in deferred custom action

Just for debugging reference. And you can use: string data = session["CustomActionData"];

Tell you what, let me slide in the code to test using VBScript so you can use message boxes. Should not be necessary, just in case you have a debugging issue:

VBScript "Simple.vbs" (save as file):

MsgBox Session.Property("CustomActionData")

WiX markup change:

<Binary Id='Simple.vbs' SourceFile="Simple.vbs" />
<CustomAction Id="MyAction" Return="check" Execute="deferred" BinaryKey="Simple.vbs" VBScriptCall="" />

Just in case that is easier. Recommend you use VBScript for debugging only. I like VBScript to get a “heartbeat” when I want to eliminate all other error sources.

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