How to create controls at runtime?

Question

How to create dynamic MFC controls and handle message maps of the controls at runtime?

Answer 1

It really depends on which controls do you want to create, especially if you want to know which flags should you set. In general it goes down to this:

Normally a CWnd-derived control is created using Create or CreateEx. For a CButton, for instance:

CButton button;
button.Create("Button text", WS_CHILD | WS_VISIBLE | WS_TABSTOP | BS_PUSHBUTTON | DT_CENTER, CRect(5, 5, 55, 19), this, nID);

where the CRect specifies the button position, this is a pointer to the parent window, and nID is the control ID.

If the control doesn't come out as expected, it's probably because some flags are missing. I suggest you draw a sample control in design mode, check out the code for that control in the RC file, and copy the flags to the Create caller.

As for the message maps, they are normally routed to the parent window. The nID value you used in Create is important here, because it will be the number that identifies the control in the message map. If you have a fixed number of controls, you can hard-code the nID numbers for your controls (starting at 10000, for instance); if not, you'll have to provide a way for the parent window to identify them. Then you just add the message map entries.

ON_BN_CLICKED(10000, OnBnClicked)
ON_CONTROL_RANGE(BN_CLICKED, 10010, 10020, OnBtnsClicked)

You can use the ON_CONTROL_RANGE message map to map a range of IDs to the same function.