如何通过WP8中的后台任务使用Xamarin Forms PCL代码？

Question

I'm trying to use the PCL code to access a SQLite database from a periodic background task in windows-phone-8.

However, I get this error: InvalidOperationException: You MUST call Xamarin.Forms.Init(); prior to using it InvalidOperationException: You MUST call Xamarin.Forms.Init(); prior to using it

Trying to do a Forms.Init() when the agent is invoked like so

    protected override void OnInvoke(ScheduledTask task)
    {
        Forms.Init();

throws UnauthorizedAccessException: Invalid cross-thread access.

Also tried Device.BeginInvokeOnMainThread(() => { Forms.Init(); }); but that also didn't work.

What is the proper way of using the common code from the PCL project in a background task?

EDIT:

• I'm calling Forms.Init() in the startup page

• Not doing any UI updates from the background task. The exception is thrown when trying to use the DependencyService to get the platform-specific connection details: DependencyService.Get<IDatabaseConection>().GetConnection();

Answer 1

Worked around the problem by using a different IoC container, as @Jason also suggested. AutoFac did the trick for me.

Tried first with TinyIoC but got the same errors referenced here : Error CS0246: The type or namespace name 'BindingFlags' could not be found. Are you missing an assembly reference? (CS0246) Error CS0246: The type or namespace name 'BindingFlags' could not be found. Are you missing an assembly reference? (CS0246) Error CS0246: The type or namespace name 'BindingFlags' could not be found. Are you missing an assembly reference? (CS0246) .

Other IoC containers that should work with Xamarin .

It's still unclear why Xamarin's IoC requires the Forms.Init() call