Specify the INSTALLLOCATION of packages in WiX inside the Burn managed bootstrapper

I have a WiX 3.6 bundle (using Burn) and managed bootstrapper that install several MSI packages. Some of the packages install to a common location (C:\program files\MyApp).

I want to let the user choose the install location inside the managed bootstrapper application (C#开发者_JAVA百科 WPF, especially because the application is large to install; about 1 GB). How can I specify the INSTALLLOCATION for each MSI packages inside my bundle?

Use an MsiProperty child for each MsiPackage to specify INSTALLLOCATION=[BurnVariable]. Then use Engine.StringVariables to set BurnVariable.

For example, in your bundle you set:

<Bundle ...>
    <Variable Name='BurnVariable' Value='bar' />
    ...
    <Chain>
        <MsiPackage Source='path\to\your.msi'>
            <MsiProperty Name="INSTALLLOCATION" Value="[BurnVariable]" />
        </MsiPackage>
    </Chain>
</Bundle>    

See also the FireGiant explanation on this topic.

Then in the managed bootstrapper you can do something similar to this:

Engine.StringVariables["BurnVariable"] = "C:\program files\MyApp";