NetInverse Developers Blog

What is Custom Action?

The Windows Installer provides many built-in actions for performing the installation process. Standard actions are sufficient to execute an installation in most cases. However, there are situations where the developer of an installation package finds it necessary to write a custom action. Custom action is a way to extend functionality of Windows« Installer. A developer can write customization code in a dll or script(like the sample below) for their specific requirements and tell Windows Installer to invoke the code at certain points during setup.

Create an xml file: product.wxs (copied from WiX.chm) as below. This WiX file will create an MSI file that copies readme.txt into “%sysdrv%/program files/test program/”.

<?xml version='1.0'?>
<WiX xmlns='http://schemas.microsoft.com/WiX/2003/01/wi'>
   <Product Id='12345678-1234-1234-1234-123456789012' Name='Test Package' Language='1033'
            Version='1.0.0.0' Manufacturer='Microsoft Corporation'>
      <Package Id='12345678-1234-1234-1234-123456789012'
                Description='My first Windows Installer package'
                Comments='This is my first attempt at creating a Windows Installer database'
                Manufacturer='Microsoft Corporation' InstallerVersion='200' Compressed='yes' />

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

      <Directory Id='TARGETDIR' Name='SourceDir'>
         <Directory Id='ProgramFilesFolder' Name='PFiles'>
            <Directory Id='MyDir' Name='TestProg' LongName='Test Program'>
               <Component Id='MyComponent' Guid='12345678-1234-1234-1234-123456789012'>
                  <File Id='readme' Name='readme.txt' DiskId='1' src='readme.txt' />
               </Component>
            </Directory>
         </Directory>
      </Directory>

      <Feature Id='MyFeature' Title='My 1st Feature' Level='1'>
         <ComponentRef Id='MyComponent' />
      </Feature>
   </Product>
</WiX>

Compile WiX file:

    c:>WiX\candle product.wxs

Link WiXObj into MSI:

    c:>WiX\light product.WiXobj

Test your first MSI:

    c:>WiX\msiexec /i product.msi

Create a customization VBS code: Customization.vbs

   function Hello
       MsgBox "Hello from customization VBS!"
   end function

By using VBS customization code you can achieve a lot of things, like creating an IIS VDIR, acling some resources, setting COM+, etc. Now you need to modify product.wxs to invoke the customization.vbs as below:

<?xml version='1.0'?>
<WiX xmlns='http://schemas.microsoft.com/WiX/2003/01/wi'>
   <Product Id='12345678-1234-1234-1234-123456789012' Name='Test Package' Language='1033'
            Version='1.0.0.0' Manufacturer='Microsoft Corporation'>
      <Package Id='12345678-1234-1234-1234-123456789012'
                Description='My first Windows Installer package'
                Comments='This is my first attempt at creating a Windows Installer database'
                Manufacturer='Microsoft Corporation' InstallerVersion='200' Compressed='yes' />

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

      <Directory Id='TARGETDIR' Name='SourceDir'>
         <Directory Id='ProgramFilesFolder' Name='PFiles'>
            <Directory Id='MyDir' Name='TestProg' LongName='Test Program'>
               <Component Id='MyComponent' Guid='12345678-1234-1234-1234-123456789012'>
                  <File Id='readme' Name='readme.txt' DiskId='1' src='readme.txt' />
               </Component>
            </Directory>
         </Directory>
      </Directory>

      <Feature Id='MyFeature' Title='My 1st Feature' Level='1'>
         <ComponentRef Id='MyComponent' />
      </Feature>

      
      <InstallExecuteSequence>
         <Custom Action="test" Sequence='1'/>
      </InstallExecuteSequence>

      <Binary Id='Customization.vbs' src='Customization.vbs'/>
      <CustomAction Id='test' BinaryKey='Customization.vbs' VBScriptCall='Hello' Return='check'/>
   </Product>
</WiX>

We add a Binary node to specify the Binary data used for CustomAction elements, and added CustomAction node to specify a custom action to be added to the MSI CustomAction table. Various combinations of the attributes for this element correspond to different custom action types. For more information about custom actions see the MSDN documentation http://msdn2.microsoft.com/en-us/library/aa372048.aspx for a “Summary List of All Custom Action Types”.

Finally we add a Custom node to sequence a custom action. Since Custom must be a child node of AdminExecuteSequence, AdminUISequence, AdvertiseExecuteSequence, InstallExecuteSequence, InstallUISequence, thus we add a InstallExecuteSequence.

Compile again:

    c:>WiX\candle product.wxs

Link again:

    c:>WiX\light product.WiXobj

Test your MSI again: now you will see a pop window coming from your WiX customization(CustomAction) code.

    c:>WiX\msiexec /i product.msi

Similiarly, you can use custom actions to create/update or start/stop your COM+ applications.

    Function ResetCOMPlus
        Set objApplicationsAdmin = CreateObject("COMAdmin.COMAdminCatalog")
        objApplicationsAdmin.ShutdownApplication "OrderCheck"
    End function