将字符转换成带有圆圈的字符
private string Convert(int m)
{
switch (m)
{
case 1: return "①";
case 2: return "②";
case 3: return "③";
case 4: return "④¹";
case 5: return "⑤";
case 6: return "⑥";
case 7: return "⑦";
case 8: return "⑧";
case 9: return "⑨";
case 10: return "⑩";
default: return "";
}
}