我已经开发了一个随机字符串生成器，但它的行为并不像我所希望的那样。我的目标是能够运行两次，并生成两个不同的四字符随机字符串。但是，它只生成一个四个字符的随机字符串两次。
下面是代码和输出示例:
private string RandomString(int size)
{
StringBuilder builder = new StringBuilder();
Random random = new Random();
char ch;
for (int i = 0; i < size; i++)
{
ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * random.NextDouble() + 65)));
builder.Append(ch);
}
return builder.ToString();
}
// get 1st random string
string Rand1 = RandomString(4);
// get 2nd random string
string Rand2 = RandomString(4);
// create full rand string
string docNum = Rand1 + "-" + Rand2;
.．.输出如下:UNTE-UNTE
.．.但它应该看起来像这个UNTE-FWNU
如何确保两个明显随机的字符串?
如果您可以访问英特尔安全密钥兼容的CPU，您可以使用这些库生成真实的随机数和字符串:https://github.com/JebteK/RdRand和https://www.rdrand.com/
从这里下载最新版本，包括Jebtek。RdRand并为其添加using语句。然后，你所需要做的就是:
bool isAvailable = RdRandom.GeneratorAvailable(); //Check to see if this is a compatible CPU
string key = RdRandom.GenerateKey(10); //Generate 10 random characters
此外，您还可以获得这些额外的功能:
string apiKey = RdRandom.GenerateAPIKey(); //Generate 64 random characters, useful for API keys
byte[] b = RdRandom.GenerateBytes(10); //Generate an array of 10 random bytes
uint i = RdRandom.GenerateUnsignedInt() //Generate a random unsigned int
如果没有兼容的CPU来执行代码，只需使用rdrand.com上的RESTful服务即可。随着rrandom包装器库包含在你的项目中，你只需要这样做(当你注册时，你会得到1000个免费电话):
string ret = Randomizer.GenerateKey(<length>, "<key>");
你也可以生成随机字节数组和无符号整数，如下所示:
uint ret = Randomizer.GenerateUInt("<key>");
byte[] ret = Randomizer.GenerateBytes(<length>, "<key>");
我创建了这个方法。
效果很好。
public static string GeneratePassword(int Lenght, int NonAlphaNumericChars)
{
string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
string allowedNonAlphaNum = "!@#$%^&*()_-+=[{]};:<>|./?";
Random rd = new Random();
if (NonAlphaNumericChars > Lenght || Lenght <= 0 || NonAlphaNumericChars < 0)
throw new ArgumentOutOfRangeException();
char[] pass = new char[Lenght];
int[] pos = new int[Lenght];
int i = 0, j = 0, temp = 0;
bool flag = false;
//Random the position values of the pos array for the string Pass
while (i < Lenght - 1)
{
j = 0;
flag = false;
temp = rd.Next(0, Lenght);
for (j = 0; j < Lenght; j++)
if (temp == pos[j])
{
flag = true;
j = Lenght;
}
if (!flag)
{
pos[i] = temp;
i++;
}
}
//Random the AlphaNumericChars
for (i = 0; i < Lenght - NonAlphaNumericChars; i++)
pass[i] = allowedChars[rd.Next(0, allowedChars.Length)];
//Random the NonAlphaNumericChars
for (i = Lenght - NonAlphaNumericChars; i < Lenght; i++)
pass[i] = allowedNonAlphaNum[rd.Next(0, allowedNonAlphaNum.Length)];
//Set the sorted array values by the pos array for the rigth posistion
char[] sorted = new char[Lenght];
for (i = 0; i < Lenght; i++)
sorted[i] = pass[pos[i]];
string Pass = new String(sorted);
return Pass;
}
public static class StringHelpers
{
public static readonly Random rnd = new Random();
public static readonly string EnglishAlphabet = "abcdefghijklmnopqrstuvwxyz";
public static readonly string RussianAlphabet = "абвгдеёжзийклмнопрстуфхцчшщъыьэюя";
public static unsafe string GenerateRandomUTF8String(int length, string alphabet)
{
if (length <= 0)
return String.Empty;
if (string.IsNullOrWhiteSpace(alphabet))
throw new ArgumentNullException("alphabet");
byte[] randomBytes = rnd.NextBytes(length);
string s = new string(alphabet[0], length);
fixed (char* p = s)
{
for (int i = 0; i < s.Length; i++)
{
*(p + i) = alphabet[randomBytes[i] % alphabet.Length];
}
}
return s;
}
public static unsafe string GenerateRandomUTF8String(int length, params UnicodeCategory[] unicodeCategories)
{
if (length <= 0)
return String.Empty;
if (unicodeCategories == null)
throw new ArgumentNullException("unicodeCategories");
if (unicodeCategories.Length == 0)
return rnd.NextString(length);
byte[] randomBytes = rnd.NextBytes(length);
string s = randomBytes.ConvertToString();
fixed (char* p = s)
{
for (int i = 0; i < s.Length; i++)
{
while (!unicodeCategories.Contains(char.GetUnicodeCategory(*(p + i))))
*(p + i) += (char)*(p + i);
}
}
return s;
}
}
你还需要这个:
public static class RandomExtensions
{
public static string NextString(this Random rnd, int length)
{
if (length <= 0)
return String.Empty;
return rnd.NextBytes(length).ConvertToString();
}
public static byte[] NextBytes(this Random rnd, int length)
{
if (length <= 0)
return new byte[0];
byte[] randomBytes = new byte[length];
rnd.NextBytes(randomBytes);
return randomBytes;
}
}
这:
public static class ByteArrayExtensions
{
public static string ConvertToString(this byte[] bytes)
{
if (bytes.Length <= 0)
return string.Empty;
char[] chars = new char[bytes.Length / sizeof(char)];
Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
return new string(chars);
}
}
还有另一个版本:我在测试中使用这种方法生成随机的伪股票代码:
Random rand = new Random();
Func<char> randChar = () => (char)rand.Next(65, 91); // upper case ascii codes
Func<int,string> randStr = null;
randStr = (x) => (x>0) ? randStr(--x)+randChar() : ""; // recursive
用法:
string str4 = randStr(4);// generates a random 4 char string
string strx = randStr(rand.next(1,5)); // random string between 1-4 chars in length
你可以重新定义randChar函数，使用一个“允许的”字符数组，而不是ascii码:
char[] allowedchars = {'A','B','C','1','2','3'};
Func<char> randChar = () => allowedchars[rand.Next(0, allowedchars.Length-1)];
