Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As _System.Windows.Forms.KeyPressEventArgs) Handles textbox1.keypress

if keys.enter then '如果这个时候按下回车，则执行下面的事件
        textbox1.text="你按了一下回车"
   end if
end sub

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        If e.KeyCode <> nothing Then   
            e.Handle=True
           else
             TextBox1.AppendText(e.KeyCode)
        End If
End Sub