"Go" writing high-quality Code 157 recommendations for improving C # programs--Recommendation 99: Overriding should not use sub-class parameters

Recommendation 99: Overriding should not use child class parameters

When overridden, if a child class parameter is used, it may deviate from the designer's intended target. For example, there is an inheritance system as follows:

    class Employee    {    }    class  manager:employee    {    }

The Setsalary method in type Managersalary now overrides the same method in salary, and the overridden method takes a subclass parameter:

    class Salary    {        publicvoid  setsalary (Employee e)        {            Console.WriteLine (" The clerk was set up a salary. ");        }    }     class managersalary:salary    {        publicvoid  setsalary (Manager m)        {            Console.WriteLine ( " the manager was set up to pay. ");        }    }

The caller's code looks like this:

        Static void Main (string[] args)        {            new  managersalary ();            M.setsalary (new  Employee ());        }

The designer's intention was to set the manager's salary, but the actual code was to set the employee's salary.

The output is:

The clerk was set up a salary.

Therefore, when overriding, the use of sub-class parameters has some risk, should avoid this design. The correct approach should still use the employee type parameter, which at least allows the compiler to remind us to use the New keyword.

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"Go" writing high-quality Code 157 recommendations for improving C # programs--Recommendation 99: Overriding should not use sub-class parameters