Context Class

This Instance is provided for convenience and can be safely used for end-product development (i.e., for the development of an individual game), but development that must incorporate or scale (i.e., library development) should rely on independently Context Instances instead. See the remarks on Context and Instance for a more detailed exploration of this topic.

This function provides an easy way for work triggered from arbitrary threads to be performed specifically on the main thread; for example, FinalAction uses this method to cause a callback invoked during destruction (which can happen on any thread) to be executed on the Unity main thread.Unity 6+ introduces improved support for asynchronous programming techniques, including a new Awaitable.MainThreadAsync⁠ which can be used for the same purpose as this method.

If an instance of the requested type already exists on this Context, that instance will be returned; otherwise, a new one will be lazily created. This method implements the "safe singleton" pattern discussed in the remarks on the Context. While the name "GetOrCreate" is used to clarify that the requested instance may be created during this call, this method should really only be thought of as an accessor with any instantiation that may or may not happen being simply an irrelevant implementation detail. Ideally, you should think of Context-local singletons as aspects of the Context itself rather than as separate instances which can be created and destroyed independently. Adhering to this thinking will ensure that order-of-operations and independent lifecycles do not complicate the usage of Context. As long as the Context merely exists, all singletons on it can always be accessed identically using GetOrCreateSingleton; all other considerations are the purview of the singletons themselves.

If an instance of the requested type already exists on this Context, that instance will be returned; otherwise, a new one will be lazily created by invoking the provided factory callback. This method differs from GetOrCreateSingleton<T> in that it accepts a factory callback, which it will invoke to create the singleton if necessary instead of simply calling new(). This is useful for singleton types which can only be constructed with arguments, or for types with private constructors. This method implements the "safe singleton" pattern discussed in the remarks on Context and further explored in the remarks on GetOrCreateSingleton<T>.