#region Linq to 字符串char.IsUpper意思是判断是否大写

            //string strDemo = "HelloWord!";

            //var query = from n in strDemo

            //            where char.IsUpper(n)

            //            select n;

            //foreach (char c in query)

            //{

            //    Console.WriteLine(c);

            //}

            #endregion