Thoughts on Level-3 linkage or level-4 linkage

Overview

1. Data sources to be initialized during page initialization:

Level I data source, level II data source, Level III data source, Level IV data source ......

Therefore, when initializing the I-level data source, you must initialize the II, III, and IV data sources.

When initializing a level II data source, you need to initialize level III and level IV, and so on ......

The most important time is to initialize the level 4 during page initialization. I have encountered an error here. record it and remind myself.

2. Changes to each level of data source are triggered by an event that changes the value of the parent level or parent level.

Here, the parent level is actually the parent level. For example, the change in the third level may be caused by the change in the first level value, so the change in the third level will follow.

Therefore, when initializing the data source, you must note that the level-2 and level-3 data sources must be initialized after the level-1 data source, so as to achieve the linkage effect.

PS: It looks very like a grasshopper on a rope...