C#为什么对象无法转换为int

Question

我只是运动有一些问题..我必须编写一个程序,询问用户N的值,然后计算N!使用递归.我写了类似的东西

 namespace ConsoleApplication19
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("This program will calculate a factorial of random number. Please type a number");
            String inputText = Console.ReadLine();
            int N = int.Parse(inputText);


        String outputText = "Factorial of " + N + "is: ";
        int result = Count(ref N);
        Console.WriteLine(outputText + result);
        Console.ReadKey();
    }

    private static object Count(ref int N)
    {
        for (int N; N > 0; N++)
        {
            return (N * N++);
        }
    }
}

问题在于"int result = Count(ref N);" 我不知道为什么它不能转换为int.如果有人能帮助我,我将不胜感激.

Answer 1

因为它返回一个对象并且对象不能隐式转换为int,你可以做的就是更改方法的签名

private static int Count(ref int N)

或者你可以做到这一点

int result = (int)Count(ref N);

举一个简单的例子

//this is what you are doing
object obj = 1;
int test = obj;   //error cannot implicitly convert object to int. Are you missing a cast?

//this is what needs to be done
object obj = 1;
int test = (int)obj; //perfectly fine as now we are casting

// in this case it is perfectly fine other way around
obj = test;  //perfectly fine as well