I'm fairly new to MVVM, so please excuse me if this problem has a well-known solution.
We are building a bunch of model classes which have some core properties that are loaded up-front, as well as some additional properties which could be lazy-loaded on demand by making a web API call (update: to clarify, it would be a web API call per lazily-loaded property).
Rather than having multiple models, it seems sensible to have a single model with the lazy-loading logic in there. However, it also seems that the lazy-loaded properties should not block when accessed, so that when the View binds to the ViewModel and it binds to the Model, we don't block the UI thread.
As such, I was thinking of a pattern something along the lines of when a lazy property on the Model is accessed it begins an asynchronous fetch and then immediately returns a default value (e.g. null). When the asynchronous fetch is complete, it will raise a PropertyChanged event so that the ViewModel/View can re-bind to the fetched value.
I've tried this out and it seems to work quite nicely, but was wondering:
- Are there any pitfalls to this approach that I haven't found out about yet, but will run into as the app increases in complexity?
- Is there an existing solution to this problem either built into the framework, or which is widely used as part of a 3rd party framework?