This is maybe a mega stupid question, but i stay looking after the keyword in vb.net

I try to write out data into a textbox, line per line... (winforms)
but this don't work this way:

TextBox1.Text += myElem.getData.getKey() & ControlChars.crlf
(.newline doesn't work either...)

Somebody knows how i can just get a list of data:

(i'm implementing an AVL tree and want to write the data of the tree out like this in a textbox

5
3
4
6
...