使用此switch语句编译时间错误

Question

我收到编译时错误

'UserQuery.ReturnInt(UserQuery.Foo)':并非所有代码路径都返回一个值

除非我在代码中没有看到某些内容,否则switch语句应该返回0作为默认值,因此所有代码路径都返回一个值.

enum Foo
{
    Bar,
    Zoo,
    Boo
}

void Main()
{
    Foo test = Foo.Bar;

    Console.WriteLine (ReturnInt(test));
}

int ReturnInt(Foo test) {

    int someOtherValue = 4; // <---Value may change depending on X

    switch (test)
    {
        case Foo.Bar:
            if (someOtherValue > 20)
                return 1;
            break;

        case Foo.Zoo:
            if (someOtherValue == 5)
                return 4;
            break;

        case Foo.Boo:
            if (someOtherValue == 2)
                return 7;
            break;

        default:
            return 0;
    }
}

Answer 1

任何其他开关块只会根据"someOtherValue"的值命中"break"语句.切换后没有return语句,因此任何触发"break"的情况都不会返回值.

Answer 2

我会改变它,以便只有一个返回点,无论如何我为了清晰的原因而喜欢它.:-)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace HelloWorld
{
    class Program
    {
        static int ReturnInt(Foo test)
        {
            int retVal = 0; // defaults to 0

            int someOtherValue = 4; // <---Value may change depending on X


            switch (test)
            {
                case Foo.Bar:

                        if (someOtherValue > 20)
                            retVal = 1;
                        break;

                case Foo.Zoo:

                        if (someOtherValue == 5)
                            retVal = 4;
                        break;

                case Foo.Boo:

                        if (someOtherValue == 2)
                            retVal = 7;
                        break;

                default:
                        retVal = 0;
                        break;

            }
            return retVal;
        }

        enum Foo
        {
            Bar,
            Zoo,
            Boo
        }

        static void Main(string[] args)
        {
            Foo test = Foo.Bar;

            Console.WriteLine(ReturnInt(test));
        }
    }
}