private int rep=0; /// <summary> /// 生成随机数字字符串 /// </summary> /// <param name="codeCount">待生成的位数</param> /// <returns>生成的数字字符串</returns> private string GenerateCheckCodeNum(int codeCount) { string str = string.Empty; long num2 = DateTime.Now.Ticks + this.rep; this.rep++; Random random = new Random(((int)(((ulong)num2) & 0xffffffffL)) | ((int)(num2 >> this.rep))); for (int i = 0; i < codeCount; i++) { int num = random.Next(); str = str + ((char)(0x30 + ((ushort)(num % 10)))).ToString(); } return str; } 方法二：随机生成字符串（数字和字母混和） /// <summary> /// 生成随机字母字符串(数字字母混和) /// </summary> /// <param name="codeCount">待生成的位数</param> /// <returns>生成的字母字符串</returns> private string GenerateCheckCode(int codeCount) { string str = string.Empty; long num2 = DateTime.Now.Ticks + this.rep; this.rep++; Random random = new Random(((int)(((ulong)num2) & 0xffffffffL)) | ((int)(num2 >> this.rep))); for (int i = 0; i < codeCount; i++) { char ch; int num = random.Next(); if ((num % 2) == 0) { ch = (char)(0x30 + ((ushort)(num % 10))); } else { ch = (char)(0x41 + ((ushort)(num % 0x1a))); } str = str + ch.ToString(); } return str; }