[说明](%E8%AF%B4%E6%98%8E.md) [接口是合约](%E6%8E%A5%E5%8F%A3%E6%98%AF%E5%90%88%E7%BA%A6.md) [实现接口的条件](%E5%AE%9E%E7%8E%B0%E6%8E%A5%E5%8F%A3%E7%9A%84%E6%9D%A1%E4%BB%B6.md) [接口值](%E6%8E%A5%E5%8F%A3%E5%80%BC.md) [类型断言](%E7%B1%BB%E5%9E%8B%E6%96%AD222%E8%A8%80.md) [通过类型断言询问行为](%E9%80%9A%E8%BF%87%E7%B1%BB%E5%9E%8B%E6%96%AD%E8%A8%80%E8%AF%A2%E9%97%AE%E8%A1%8C%E4%B8%BA.md) [类型开关](%E7%B1%BB%E5%9E%8B%E5%BC%80%E5%85%B3.md)