The brothers do projects before, I used VB.Net, I met a lot of problems. I believe that many beginners will encounter these problems. For beginners to learn, the younger brother summed up some small experiences for your reference. discuss. First: How to control the properties of the parent form in the MDI child form: For example, after opening a sub-form, set a menu item or button in the parent form to an invisible state, and so.
