In Blazor a razor component goes through some lifecycle events before and after rendering. There is also support in Blazor to pre-render the component, which will also influence when the component is rendered. It is important to understand when these events are called by the platform to be able to make calls to subcomponents or interop calls to JavaScript at the appropriate time, else it will result in exceptions due to non-existent components. It is also vital to know when you can perform calls that will result in lengthy operations in your code, to not block the component from rendering.
(More to come soon …)