public static async Task <CoverEditorViewModel> FromAsync(CoverManager manager, ICoverParent coverParent)
{
var viewModel = new CoverEditorViewModel
{
coverId = coverParent.CoverId
};
if (viewModel.coverId == null) // since cover id equal id, new object may contain null cover id.
{
throw new ArgumentNullException();
}
else
{
var cover = await manager.FindAsync(viewModel.coverId);
if (cover == null)
{
viewModel.CreateMode();
}
else
{
viewModel.ModifyMode(cover);
}
}
return(viewModel);
}
