c#使用maskedTextBox控件IP地址输入按“.”跳到下一段

private void maskedTextBox1_KeyDown(object sender, KeyEventArgs e) { if (e.KeyValue == 110 || e.KeyValue == 190)//小键盘的.是110，主键盘的.是190,按.后跳到下一段 switch (maskedTextBox1.SelectionStart) { case 0: case 1: case 2: case 3: maskedTextBox1.SelectionStart = 4; break; case 4: case 5: case 6: case 7: maskedTextBox1.SelectionStart = 8; break; case 8: case 9: case 10: case 11: maskedTextBox1.SelectionStart = 12; break; default: break; } }