C# 如何重写ToString方法

Demo1：加上价格标签

class Program
    {
        public decimal price { get; set; }
        static void Main(string[] args)
        {
            Program p = new Program();
            p.price = 25;
            Console.WriteLine(p.ToString());
            Console.ReadKey();
        }

        public override string ToString()
        {
            return "$"+price.ToString();
        }
    }

Demo2：修改时间的输出格式

 public DateTime time { get; set; }
        static void Main(string[] args)
        {
            Program p = new Program();

            p.time = DateTime.Now;

            Console.WriteLine(p.ToString());

            Console.ReadKey();
        }

        public override string ToString()
        {
            return string.Format("{0}年{1}月{2}日",time.Year,time.Month,time.Day);
        }

Demo3：

public override string ToString()
{
StringBuilder builder = new StringBuilder(16);
bool firstTime = true;
foreach (T item in this)
{
if (firstTime)
{
firstTime = false;
}
else
{
builder.AppendLine();
}
builder.Append(item);
}
return builder.ToString();
}