产生有序的全局唯一Id

//利用时间和Guid作为种子产生随机数
private string GenerateUniqueID()
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
string str1 = DateTime.Now.ToString("yyyyMMddHHmmss");
Random d = new Random(Guid.NewGuid().GetHashCode());
string str2 = d.Next(10000, 100000).ToString();
return sb.Append(str1).Append(str2).ToString();
}
　　

//利用时间和RNGCryptoServiceProvider产生
public static string GenerateOrderNumber()
{
string strDateTimeNumber = DateTime.Now.ToString("yyyyMMddHHmmssms");
string strRandomResult = NextRandom(1000, 1).ToString();
return strDateTimeNumber + strRandomResult;
}

/// <summary>
/// 参考：msdn上的RNGCryptoServiceProvider例子
/// </summary>
/// <param name="numSeeds"></param>
/// <param name="length"></param>
/// <returns></returns>
private static int NextRandom(int numSeeds, int length)
{
// Create a byte array to hold the random value.
byte[] randomNumber = new byte[length];
// Create a new instance of the RNGCryptoServiceProvider.
System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider();
// Fill the array with a random value.
rng.GetBytes(randomNumber);
// Convert the byte to an uint value to make the modulus operation easier.
uint randomResult = 0x0;
for (int i = 0; i < length; i++)
{
randomResult |= ((uint)randomNumber[i] << ((length - 1 - i) * 8));
}
return (int)(randomResult % numSeeds) + 1;
}