Downloading packages

As we saw in the previous chapter, we can download a package from the Internet or a local network, as in the following example where we use the NetFx40Web package from WixNetFxExtension to download the .NET Framework:

<Chain>
   <PackageGroupRef Id="NetFx40Web"/>
   <MsiPackage SourceFile="Lib\MyInstaller.msi" />
</Chain>

In order for our custom UI to allow this download to proceed, we must handle the ResolveSource event. The following is an example that uses an anonymous method in our viewmodel's constructor:

this.model.BootstrapperApplication.ResolveSource += 
   (sender, args) => 
{ 
   if (!string.IsNullOrEmpty(args.DownloadSource))
   { 
      // Downloadable package found 
      args.Result = Result.Download; 
   } 
   else 
   { 
      // Not downloadable 
      args.Result = Result.Ok; 
   } 
};

We check if the package has a DownloadSource attribute and if it does, we set the Result property to Result.Download. This will allow the download...