摘要：
isBooleantruefalseisif(o is Employee)...{Employee e=(Employee) o;}CLRisoEmployeeifCLRoEmployeeCLRCLRoCLR(Employee)Employee e=o as Employee;if(e!=null)...{}CLRoEmployee;asnulloEmployeeasnullasCLRifenull.asnullnullSystem.NullReferenceExceptionc# isas isas2istruefalsetruefalseisSystem.Boolean b1 = (o i 阅读全文
