how to close the dialog box on connection?

See more:

.NET3.0

C++

.NET

MFC

VisualC++

I have made a dialog box/form in vc++ MFC which should take the inputs from user(username,password)and if the username ,password is correct it shows the message connecting in another form,and if the inputs are not correct the form should not close. my code is below:

void LoginCredentials::OnBnClickedOk()
{
    // TODO: Add your control notification handler code here
    if (UpdateData(TRUE))
    {
        this->ShowWindow(FALSE);
    }
    else
    {
      this->ShowWindow(TRUE);
    }

}

but even if the inputs are incorrect,form gets closed..can anybody help me or suggest me,any kind of help will be appreciated.