Here is an example of wxTextValidator usage.
\begin{verbatim}
- wxTextCtrl *txt1 = new wxTextCtrl(this, VALIDATE_TEXT, "",
+ wxTextCtrl *txt1 = new wxTextCtrl(this, -1, wxT(""),
wxPoint(10, 10), wxSize(100, 80), 0,
wxTextValidator(wxFILTER_ALPHA, &g_data.m_string));
\end{verbatim}