正如我在其他答案的 cmets 中提到的，它可能不足以满足您的目的。我编写了更多代码来生成一串随机的字母数字字符。这一次，它们不限于 0-9 和 A-F - 即随机生成的 nibbles 的十六进制等价物。相反，它们由完整范围的字母数字字符组成，至少包含大写字母。鉴于我们将从 16 个可能的十六进制字符变为 36 个可能的字符（完整的字母表和 0-9），这应该足以增加唯一性的潜力。
不过，当我运行它超过 10,000,000 次尝试时，仍然有很多重复。这只是野兽的本性：你会用这么短的字符串被骗的可能性相当高。无论如何，它就在这里。你可以玩弄它。如果您的客户不介意小写字母 - 例如如果“RORYAP”与“RoryAp”不同——那将进一步增加唯一性的可能性。
/// <summary>
/// Instances of this class are used to geneate alpha-numeric strings.
/// </summary>
public sealed class AlphaNumericStringGenerator
{
/// <summary>
/// The synchronization lock.
/// </summary>
private object _lock = new object();
/// <summary>
/// The cryptographically-strong random number generator.
/// </summary>
private RNGCryptoServiceProvider _crypto = new RNGCryptoServiceProvider();
/// <summary>
/// Construct a new instance of this class.
/// </summary>
public AlphaNumericStringGenerator()
{
//Nothing to do here.
}
/// <summary>
/// Return a string of the provided length comprised of only uppercase alpha-numeric characters each of which are
/// selected randomly.
/// </summary>
/// <param name="ofLength">The length of the string which will be returned.</param>
/// <returns>Return a string of the provided length comprised of only uppercase alpha-numeric characters each of which are
/// selected randomly.</returns>
public string GetRandomUppercaseAlphaNumericValue(int ofLength)
{
lock (_lock)
{
var builder = new StringBuilder();
for (int i = 1; i <= ofLength; i++)
{
builder.Append(GetRandomUppercaseAphanumericCharacter());
}
return builder.ToString();
}
}
/// <summary>
/// Return a randomly-generated uppercase alpha-numeric character (A-Z or 0-9).
/// </summary>
/// <returns>Return a randomly-generated uppercase alpha-numeric character (A-Z or 0-9).</returns>
private char GetRandomUppercaseAphanumericCharacter()
{
var possibleAlphaNumericValues =
new char[]{'A','B','C','D','E','F','G','H','I','J','K','L',
'M','N','O','P','Q','R','S','T','U','V','W','X','Y',
'Z','0','1','2','3','4','5','6','7','8','9'};
return possibleAlphaNumericValues[GetRandomInteger(0, possibleAlphaNumericValues.Length - 1)];
}
/// <summary>
/// Return a random integer between a lower bound and an upper bound.
/// </summary>
/// <param name="lowerBound">The lower-bound of the random integer that will be returned.</param>
/// <param name="upperBound">The upper-bound of the random integer that will be returned.</param>
/// <returns> Return a random integer between a lower bound and an upper bound.</returns>
private int GetRandomInteger(int lowerBound, int upperBound)
{
uint scale = uint.MaxValue;
// we never want the value to exceed the maximum for a uint,
// so loop this until something less than max is found.
while (scale == uint.MaxValue)
{
byte[] fourBytes = new byte[4];
_crypto.GetBytes(fourBytes); // Get four random bytes.
scale = BitConverter.ToUInt32(fourBytes, 0); // Convert that into an uint.
}
var scaledPercentageOfMax = (scale / (double) uint.MaxValue); // get a value which is the percentage value where scale lies between a uint's min (0) and max value.
var range = upperBound - lowerBound;
var scaledRange = range * scaledPercentageOfMax; // scale the range based on the percentage value
return (int) (lowerBound + scaledRange);
}
}