list box problem

[GCDEF]

Thanks for you reply.
But unfortunately I don't know what my string is."Hello World!Hello World!" was an example.
In fact I'm writing a packet sniffer and I wanna show whole the data of each packet, into a separated box(this critical box)
So i'm not able to use that
m_myControl.SetWindowText(_T("1st part of string\r\n 2nd part of string"));
for going to the next line.

As I said, an edit or static control will wrap for you.