Mergers

Fragments help divide a large package into manageable chunks of source code and make developer co-operation and code reuse possible. Therefore, it is best suited to in-house development where WiX source code can and will be shared. But there is another mechanism more capable of providing complete installation packages for other parties to use: merge modules. If, say, your product A depends on product B of another vendor, you can use their merge module meant to install their product and make it a part of your own so that both will be installed at the same time.

Setting up a merge module is very similar to the standalone source files we've used so far. However, instead of a Product, we specify a Module tag. Unlike with earlier packages, here we have to provide a unique GUID ourselves:

<?xml version="1.0" encoding="windows-1252"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
  <Module Id="File1" Language="0" Version="1.2.3">

    <Package Id="YOURGUID-8DEE-4410-990A-1802896C4209" InstallerVersion="100"
      Languages="1033" Manufacturer="dev" SummaryCodepage="1252" AdminImage="no" />

      <Directory Id='TARGETDIR' Name='SourceDir'>
        <Directory Id='ProgramFilesFolder' Name='PFiles'>
          <Directory Id='Acme' Name='Acme'>
            <Directory Id='INSTALLDIR' Name='Foobar 1.0'>

              <Component Id="File1" Guid="YOURGUID-CF0E-40AB-ACC5-0E9A5F112628">
                <File Id="File1.txt" Name="File1.txt" Source="File1.txt" KeyPath='yes' />
              </Component>

            </Directory>
          </Directory>
        </Directory>
      </Directory>

  </Module>
</Wix>

In our sample, we use a second merge module as well. Its source file almost identical to the previous one, with the following differences: we refer to a different file to deploy and we include a Dependency tag to indicate that the second module is dependent on the first one. For the dependency, we use the Module Id identifier with the module's Package GUID appended—but we have to replace the original dashes by underscore characters:

  <Module Id="File2" Language="0" Version="1.2.3">
    ...
    <File Id="File2.txt" Name="File2.txt" Source="File2.txt" KeyPath='yes' />
    ...
    <Dependency RequiredId="File1.YOURGUID_8DEE_4410_990A_1802896C4209"
      RequiredLanguage="0" RequiredVersion="1.2.3" />
  </Module>

To create a unified installation package, we write a usual standalone WiX source file:

<?xml version="1.0" encoding="windows-1252"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
  <Product Name='Foobar 1.0' Id='YOURGUID-86C7-4D14-AEC0-86416A69ABDE' UpgradeCode='YOURGUID-7349-453F-94F6-BCB5110BA4FD'
    Language='1033' Codepage='1252' Version='1.0.0' Manufacturer='Acme Ltd.'>

    <Package Id='*' Keywords='Installer' Description="Acme's Foobar 1.0 Installer"
      Comments='Foobar is a registered trademark of Acme Ltd.' Manufacturer='Acme Ltd.'
      InstallerVersion='100' Languages='1033' Compressed='yes' SummaryCodepage='1252' />

    <Media Id="1" Cabinet="product.cab" EmbedCab="yes" />

    <Directory Id='TARGETDIR' Name='SourceDir'>
      <Directory Id='ProgramFilesFolder' Name='PFiles'>
        <Directory Id='Acme' Name='Acme'>
          <Directory Id='INSTALLDIR' Name='Foobar 1.0'>

Instead of the usual components, we refer to the merge modules. The SourceFile mentions the .msm files:

            <Merge Id="file1" Language="1033" SourceFile="Module1.msm" DiskId="1" />
            <Merge Id="file2" Language="1033" SourceFile="Module2.msm" DiskId="1" />

          </Directory>
        </Directory>
      </Directory>
    </Directory>

    <Feature Id="Msm" Title="Msm" Level="1">
      <MergeRef Id="file1" />
      <MergeRef Id="file2" />
    </Feature>

  </Product>
</Wix>

You can download the complete SampleMergeModule. You need to build the merge modules separately:

candle.exe Module1.wxs
light.exe Module1.wixobj

candle.exe Module2.wxs
light.exe Module2.wixobj

candle.exe SampleMerge.wxs
light.exe SampleMerge.wixobj