Binding of customer control dropdownlist

Because of the override databind event, the user control defined by myself will re-execute the databind method every time the page is PostBack. It turns out that the this. databind () method is executed in the oninit () event.

In this way, when loading a page, you do not need to manually bind the dropdownlist, and DDL can load data directly. The negative effect of this is that the page response time is lost, after each PostBack of the page, the oninit () event of the control will be executed. As a result, if databind () takes too long, the page RESPONSE event will be slow, in particular, multiple pages similar to dropdownlist are used.