int i = 124344343;
            byte[] bs = new byte[sizeof(int)];
            bs = BitConverter.GetBytes(i);
            foreach (char c in bs)
            {
                MessageBox.Show(Convert.ToString(c));
            }

------解决方案--------------------

C# code

         public string test(int flag)
        {
            if (flag >= 0 && flag <= 255)
            {
                System.Text.ASCIIEncoding ascEn = new System.Text.ASCIIEncoding();
                byte[] arr = new byte[] { (byte)flag };
                string str = ascEn.GetString(arr);
                return (str);
            }
            else
            {
                return null;
            }
        }

------解决方案--------------------
C# code

            decimal dm = 909391681;
            byte[] by = BitConverter.GetBytes(decimal.ToInt64(dm));
            string acs = Encoding.ASCII.GetString(by);//貌似多了几个\0