StorageFile Async usage in a NON Metro application

Question

I am trying to create an instance of StorageFile in my class library...

var localFolder = ApplicationData.Current.LocalFolder;
StorageFile destinationFile = await localFolder.CreateFileAsync(destination, CreationCollisionOption.GenerateUniqueName);

VS11 is not building say: 'await' requires that the type 'Windows.Foundation.IAsyncOperation' have a suitable GetAwaiter method. Are you missing a using directive for 'System'?

obviously I am using .net 4.5 as target and I am referencing Windows Assemblies... not sure why this code work in MetroStyle but does not build in a class library... How can I create an instance of Storagefile in a class library??? at this stage it is not important if the file is created in an async way...

pls let me know your thoughts... Stelio

Answer 1

What worked for me is to "manually" add the TargetPlatformVersion

<PropertyGroup>
  <TargetPlatformVersion>8.0</TargetPlatformVersion>
</PropertyGroup>

and in Item group add the following

<ItemGroup>
  <Reference Include="System.Runtime.WindowsRuntime" />
  <Reference Include="System.Runtime" />
  <Reference Include="Windows" />
</ItemGroup>

Then the project should compile normaly.