Windows message daily training-wm_command

When a user clicks a menu, button, drop-down list box, or other controls, wm_command is triggered.

Loword (wparam) is the control, menu, or acceleration key ID. The sparator ID of the menu is 0.

If loword (wparam) is the Control ID and hiword (wparam) is the notification code, such as bn_clicked and bn_dblclk, it indicates the user's operations on the control, double-click, and click.

If loword (wparam) is the menu ID, hiword (wparam) is 0.

If loword (wparam) is the accelerator ID, hiword (wparam) is 1.

If loword (wparam) is the Control ID and lparam is the control handle value, otherwise it is null. Actually, getdlgitem (hwnd, loword (wparam) = lparam.

Notification code naming rules:

List box: LBN _*****

Combo box: CBN _****

Tab box: TBN _****

Button: BN _*****

Edit: en _*****