For Windows programming, the values of different objects are different. Be careful

Currently, there are several classes: Class A is the dll library, Class B calls a, and is also encapsulated into a dll library. There is also a DLG dialog box class that calls Class B, then there is a directory in the dialog box, and a button on the directory pops up in another dialog box. At the beginning, I also defined a B * pdlg1 IN THE subdialog box; in the parent dialog box, a B * pdlg is defined, and the value of the member variables of Class A is obtained separately. The subdialog box cannot be obtained, the pointer in the parent dialog box is changed later, and the member variable of a is operated through the parent dialog box in the subdialog box. This is correct!