MSDN 隐式运算符示例

class Digit
{
    public Digit(double d) { val = d; }
    public double val;

    // User-defined conversion from Digit to double
    public static implicit operator double(Digit d)
    {
        Console.WriteLine("Digit to double implict conversion called");
        return d.val;
    }
    //  User-defined conversion from double to Digit
    public static implicit operator Digit(double d)
    {
        Console.WriteLine("double to Digit implict conversion called");
        return new Digit(d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Digit dig = new Digit(7);
        //This call invokes the implicit "double" operator
        double num = dig;
        //This call invokes the implicit "Digit" operator
        Digit dig2 = 12;
        Console.WriteLine("num = {0} dig2 = {1}", num, dig2.val);
        Console.ReadLine();
    }
}

输出：

数字加双重隐含转换称为
双数字数字冲突转换，称为
num = 7 dig2 = 12

.NET 小提琴现场演示