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?
这个解决方案是Random类的扩展。
使用
class Program
{
private static Random random = new Random();
static void Main(string[] args)
{
random.NextString(10); // "cH*%I\fUWH0"
random.NextString(10); // "Cw&N%27+EM"
random.NextString(10); // "0LZ}nEJ}_-"
random.NextString(); // "kFmeget80LZ}nEJ}_-"
}
}
实现
public static class RandomEx
{
/// <summary>
/// Generates random string of printable ASCII symbols of a given length
/// </summary>
/// <param name="r">instance of the Random class</param>
/// <param name="length">length of a random string</param>
/// <returns>Random string of a given length</returns>
public static string NextString(this Random r, int length)
{
var data = new byte[length];
for (int i = 0; i < data.Length; i++)
{
// All ASCII symbols: printable and non-printable
// data[i] = (byte)r.Next(0, 128);
// Only printable ASCII
data[i] = (byte)r.Next(32, 127);
}
var encoding = new ASCIIEncoding();
return encoding.GetString(data);
}
/// <summary>
/// Generates random string of printable ASCII symbols
/// with random length of 10 to 20 chars
/// </summary>
/// <param name="r">instance of the Random class</param>
/// <returns>Random string of a random length between 10 and 20 chars</returns>
public static string NextString(this Random r)
{
int length = r.Next(10, 21);
return NextString(r, length);
}
}
我发现这更有帮助，因为它是一个扩展，它允许您选择代码的源代码。
static string
numbers = "0123456789",
letters = "abcdefghijklmnopqrstvwxyz",
lettersUp = letters.ToUpper(),
codeAll = numbers + letters + lettersUp;
static Random m_rand = new Random();
public static string GenerateCode(this int size)
{
return size.GenerateCode(CodeGeneratorType.All);
}
public static string GenerateCode(this int size, CodeGeneratorType type)
{
string source;
if (type == CodeGeneratorType.All)
{
source = codeAll;
}
else
{
StringBuilder sourceBuilder = new StringBuilder();
if ((type & CodeGeneratorType.Letters) == CodeGeneratorType.Numbers)
sourceBuilder.Append(numbers);
if ((type & CodeGeneratorType.Letters) == CodeGeneratorType.Letters)
sourceBuilder.Append(letters);
if ((type & CodeGeneratorType.Letters) == CodeGeneratorType.LettersUpperCase)
sourceBuilder.Append(lettersUp);
source = sourceBuilder.ToString();
}
return size.GenerateCode(source);
}
public static string GenerateCode(this int size, string source)
{
StringBuilder code = new StringBuilder();
int maxIndex = source.Length-1;
for (int i = 0; i < size; i++)
{
code.Append(source[Convert.ToInt32(Math.Round(m_rand.NextDouble() * maxIndex))]);
}
return code.ToString();
}
public enum CodeGeneratorType { Numbers = 1, Letters = 2, LettersUpperCase = 4, All = 16 };
希望这能有所帮助。
字符串生成器的另一个版本。简单，没有花哨的数学和神奇的数字。而是用一些神奇的字符串来指定允许的字符。
更新:
我将generator设置为静态的，因此当多次调用时，它将不会返回相同的字符串。然而，此代码不是线程安全的，并且绝对不是加密安全的。
对于密码生成，应该使用System.Security.Cryptography.RNGCryptoServiceProvider。
private Random _random = new Random(Environment.TickCount);
public string RandomString(int length)
{
string chars = "0123456789abcdefghijklmnopqrstuvwxyz";
StringBuilder builder = new StringBuilder(length);
for (int i = 0; i < length; ++i)
builder.Append(chars[_random.Next(chars.Length)]);
return builder.ToString();
}
