Programmatically populate textbox control multiline in loop

Hi, could someone please help me, I've spent entirely too much time nearly ripping my hair out over such a seemingly trivial piece of code...
I have a textbox control that gets populated with an employee's name, and then gets populated with another employee's name, which should go to the next line... I cannot for the life of me get this thing to work correctly, it always doubles up the previous employees...
  While (rdr.Read()) If EmployeeNameTextBox.Text = String.Empty Then EmployeeNameTextBox.Text = rdr("EmployeeFirstName").ToString() + " " + rdr("EmployeeLastName").ToString() Else EmployeeNameTextBox.Text = Employe ...