[wix-users] CustomAction - both Read AND Write Properties

Walter Dexter wfdexter at gmail.com
Wed Oct 16 12:40:18 PDT 2019

Can someone confirm this is impossible so I can stop banging my head on the
wall - or tell me how to do it?

I'm writing a CustomAction in C#. I wanted to pass in some of the MSI
properties, lookup some stuff in files on the file system and set some more
of the MSI properties.

   - If I set the Execute attribute to "immediate" then CustomActionData
   (that I setup with a type 51 custom action) doesn't get passed in, but I
   can update the MSI properties from the CA.
   - If I set the Execute attribute to "deferred" then CustomActionData
   does get passed in, but I can't update the MSI properties from the CA.
   - There don't appear to be any other Execute attribute values that make
   any sense to make it any better.

I'm pasting in the relevant chunk of my WXS file below.

What's going on here is the DLL CA looks in a strangely formatted text file
("DNS.TXT") to get the DNS servers from "nar.na.test" and "nar.na.corp"
records, then IN_STAGING property is used to decide which set to write to
the INI file.

IN_STAGING is set if a flag file (staging.flag) exists. I'm just working
off the requirements handed me, but I assume that file would be created on
our test systems but not in production locations.

If there's something else I've done that is stupid I'm glad to hear that
feedback as well. :)

I'm probably going to give up and just hard-code the three properties in
the CA DLL but I didn't really want to. I wanted the DLL to be as
non-specific as possible and all that sort of stuff passed in from the MSI
so when they decide that everything needs to be somewhere else I can just
tweak a property and move on.

Thanks for any help-


<!-- Where to find the DNS addresses -->
<Property Id="DNS_TXT_FILE"    Value="c:\pos_backup\network\dns.txt"
Secure="yes" />

<!-- staging and production domain names -->
<Property Id="STAGING_DOMAIN"  Value="nar.na.test" Secure="yes" />
<Property Id="PROD_DOMAIN"     Value="nar.na.corp" Secure="yes" />

<!-- config file to update -->
<Property Id="CONFIG_INI_PATH"
Value="c:\pos_backup\storage\xpestaging\tools\config.ini" Secure="yes" />

<!-- Package up the above properties for the custom action to use. -->
<CustomAction Id="CA_GetDNSDLL_Properties" Return="check"


<!-- Custom action puts DNS servers in these properties. -->
<Property Id="PRI_PROD" Secure="yes" />
<Property Id="SEC_PROD" Secure="yes" />
<Property Id="PRI_STAGING" Secure="yes" />
<Property Id="SEC_STAGING" Secure="yes" />

<!-- Determine if staging.flag file exists and therefore if system is in
staging. Otherwise production -->
<Property Id="IN_STAGING" Secure="yes" >
    <DirectorySearch Id="DS_IN_STAGING" Path="DIR_ISPCONFIG" >
        <FileSearch Id="FS_IN_STAGING" Name="staging.flag" />

<!-- Get the DNS addresses -->
<Binary Id="GetDNSDLL"
SourceFile="..\..\source\GetDNSCA\obj\x86\Release\GetDNS.CA.dll" />
<CustomAction Id="CA_GetDNSDLL" BinaryKey="GetDNSDLL" DllEntry="GetDNS"
Execute="immediate" Return="check" />

<!-- Update the config.ini file - production values. -->
<Feature Id="W10_CONFIGINI_DNS" Title="Set CONFIG.INI DNS for Windows 10
project" Level="1" >

    <!-- Not in staging = production. -->
    <Component Id="CMP_PROD_DNS" Directory="DIR_STAGING"
Guid="{869128EF-0FCA-4B44-B935-CA22079134FE}" Transitive="yes" >
Source="files/config.proddns.dll" KeyPath="yes" />
        <IniFile Id="IF_PROD_DNS_PRI" Name="config.ini" Action="addLine"
Directory="DIR_STAGING" Section="Network" Key="DNS_PRIMARY"
Value="[PRI_PROD]" />
        <IniFile Id="IF_PROD_DNS_SEC" Name="config.ini" Action="addLine"
Directory="DIR_STAGING" Section="Network" Key="DNS_SECONDARY"
Value="[SEC_PROD]" />
        <Condition><![CDATA[NOT IN_STAGING]]></Condition>

    <!-- In staging = staging. -->
    <Component Id="CMP_STAGING_DNS" Directory="DIR_STAGING"
 Guid="{1F10F5D4-BDD7-4718-8BD2-3F5CFAA391EB}" Transitive="yes" >
Source="files/config.stagdns.dll" KeyPath="yes" />
        <IniFile Id="IF_STAGING_DNS_PRI" Name="config.ini" Action="addLine"
Directory="DIR_STAGING" Section="Network" Key="DNS_PRIMARY"
Value="[PRI_STAGING]" />
        <IniFile Id="IF_STAGING_DNS_SEC" Name="config.ini" Action="addLine"
Directory="DIR_STAGING" Section="Network" Key="DNS_SECONDARY"
Value="[SEC_STAGING]" />


    <RemoveExistingProducts After="InstallInitialize" />
    <!-- These three also for Windows 10 Config.ini change -->
    <!-- Suppress the INI value remove because the uninstall will also be
deleting the whole file. -->
    <!-- CA_GetDNSDLL pulls the DNS addresses out of the DNS.TXT file. -->
    <Custom Action="CA_GetDNSDLL_Properties" Before="CA_GetDNSDLL" />
    <!-- <Custom Action="CA_GetDNSDLL" Before="CostFinalize" /> was this
before I changed the CA above to deferred from immediate.-->
    <Custom Action="CA_GetDNSDLL" Before="WriteIniValues" />

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