Making Merge Modules (msm) more configurable…

I rarely have to face this, but have to, that is: develop merge modules which can be configured at runtime. Recently, I developed a merge module which is to write it files location in an INI file. And the location of INI file can’t be hard coded inside. So using  Configuration and  Substitution elements, we can achieve this goal. Here is the code segment:

Wix Merge Module using Configuration and Substitution elements:

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
  <Module Id="FasterGPS"
          Language="1033"
          Version="1.0.0.0">
    <Package Id="{4DDF212E-E8A8-47E6-A010-DDF8D763866C}"
             InstallerVersion="200"
             Manufacturer="PUT-COMPANY-NAME-HERE" />
    <Configuration Name="CONFIGURABLE_AT_INI_FOLDER"
                   Format="Key"
                   Type="Directory"
                   ContextData="IsolationDir"
                   DefaultValue="INSTALLDIR"
                   NonNullable="yes"
                   DisplayName="AT.ini Folder"
                   Description="AT.ini Folder" />
    <Substitution Table="Directory"
                  Row="INI_FOLDER"
                  Column="Directory_Parent"
                  Value="[=CONFIGURABLE_AT_INI_FOLDER]" />
    <Directory Id="TARGETDIR"
               Name="SourceDir">
      <Directory Id="INI_FOLDER" />
      <Directory Id="ME">
        <Component Id="FasterGPS.apk"
                   Guid="{B43FA0CC-4C3D-481B-8521-4667D7701D37}">
          <File Id="FasterGPS.apk"
                KeyPath="yes"
                Source="FasterGPS.apk" />
          <IniFile Id="MyLocationINI"
                   Action="createLine"
                   Directory="INI_FOLDER"
                   Key="CUSTOM_ROOT"
                   Name="MyConfig.ini"
                   Section="ALIAS"
                   Value="[ME]" />
        </Component>
      </Directory>
    </Directory>
  </Module>
</Wix>

Now when you use the merge module, you will have to define ConfigurationData element as mentioned below:

WIX passing Configuration Data to Merge Module:

<Directory Id="MY_INI_FOLDER" >
  <Component Id="MyINIFile"
             Guid="{52B0F9A2-E91C-4CE3-B3A8-0F29EC45DBF3}">
    <File Id="MyINIFile"
          KeyPath="yes"
          Source="MyConfig.ini" />
  </Component>
</Directory>
<Directory Id="SUB"
           Name="Sub apps">
  <Merge Id="FG"
         DiskId="1"
         SourceFile="FasterGPS.apk.msm"
         Language="1033" >
    <ConfigurationData Name="CONFIGURABLE_AT_INI_FOLDER"
                       Value="MY_INI_FOLDER" />
  </Merge>
</Directory>

At run time, value of "MY_INI_FOLDER" would be passed to merge module and would be received in CONFIGURABLE_AT_INI_FOLDER and would be Substituted in Directory Table record for "INI_FOLDER";