private static IMvxViewModel LoadViewModel(this IMvxElement element)
{
if (MvxDesignTimeChecker.IsDesignTime)
{
return(new MvxNullViewModel());
}
var viewModelType = element.FindAssociatedViewModelTypeOrNull();
if (viewModelType == typeof(MvxNullViewModel))
{
return(new MvxNullViewModel());
}
if (viewModelType == null ||
viewModelType == typeof(IMvxViewModel))
{
MvxFormsLog.Instance.Trace("No ViewModel class specified for {0} in LoadViewModel",
element.GetType().Name);
return(null);
}
var loader = Mvx.IoCProvider.Resolve <IMvxViewModelLoader>();
var viewModel = loader.LoadViewModel(new MvxViewModelRequest(viewModelType), null);
if (viewModel == null)
{
throw new MvxException("ViewModel not loaded for " + viewModelType);
}
return(viewModel);
}
public static void OnViewAppearing(this IMvxElement element)
{
var cache = Mvx.Resolve <IMvxChildViewModelCache>();
var cached = cache.Get(element.FindAssociatedViewModelTypeOrNull());
element.OnViewCreate(() => cached ?? element.LoadViewModel());
}
private static void LoadViewModelForElement(IMvxElement element)
{
IMvxViewModel cached = null;
if (!MvxDesignTimeChecker.IsDesignTime)
{
var cache = Mvx.IoCProvider.Resolve <IMvxChildViewModelCache>();
cached = cache.Get(element.FindAssociatedViewModelTypeOrNull());
}
element.OnViewCreate(() => cached ?? element.LoadViewModel());
}
private static async ValueTask LoadViewModelForElementAsync(IMvxElement element)
{
IMvxViewModel?cached = null;
if (!MvxDesignTimeChecker.IsDesignTime)
{
var cache = Mvx.IoCProvider.Resolve <IMvxChildViewModelCache>();
cached = cache.Get(element.FindAssociatedViewModelTypeOrNull());
}
await element.OnViewCreate(async() =>
{
return(cached ?? await element.LoadViewModel().ConfigureAwait(false));
}
).ConfigureAwait(false);
}
public static void OnViewAppearing(this IMvxElement element)
{
LoadViewModelForElement(element);
}
public static void OnBindingContextChanged(this IMvxElement element)
{
LoadViewModelForElement(element);
}
public static ValueTask OnViewAppearing(this IMvxElement element)
{
return(LoadViewModelForElementAsync(element));
}
public static ValueTask OnBindingContextChanged(this IMvxElement element)
{
return(LoadViewModelForElementAsync(element));
}
