我如何在c#中生成一个随机的8个字符的字母数字字符串?
当前回答
不是100%确定，因为我没有测试这里的每个选项，但在我测试的选项中，这个是最快的。用秒表计时，它显示9-10滴答，所以如果速度比安全更重要，试试这个:
private static Random random = new Random();
public static string Random(int length)
{
var stringChars = new char[length];
for (int i = 0; i < length; i++)
{
stringChars[i] = (char)random.Next(0x30, 0x7a);
return new string(stringChars);
}
}
其他回答
下面是Eric J的解决方案的一个变体，即加密声音，用于WinRT (Windows商店应用程序):
public static string GenerateRandomString(int length)
{
var chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
var result = new StringBuilder(length);
for (int i = 0; i < length; ++i)
{
result.Append(CryptographicBuffer.GenerateRandomNumber() % chars.Length);
}
return result.ToString();
}
如果性能很重要(特别是当长度很高时):
public static string GenerateRandomString(int length)
{
var chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
var result = new System.Text.StringBuilder(length);
var bytes = CryptographicBuffer.GenerateRandom((uint)length * 4).ToArray();
for (int i = 0; i < bytes.Length; i += 4)
{
result.Append(BitConverter.ToUInt32(bytes, i) % chars.Length);
}
return result.ToString();
}
我不知道这在密码学上听起来如何，但它比迄今为止(在我看来)更复杂的解决方案更具可读性和简练性，而且它应该比系统更“随机”。Random-based解决方案。
return alphabet
.OrderBy(c => Guid.NewGuid())
.Take(strLength)
.Aggregate(
new StringBuilder(),
(builder, c) => builder.Append(c))
.ToString();
我不知道我认为这个版本还是下一个版本“更漂亮”，但它们给出了完全相同的结果:
return new string(alphabet
.OrderBy(o => Guid.NewGuid())
.Take(strLength)
.ToArray());
当然，它并没有针对速度进行优化，所以如果每秒生成数百万个随机字符串是关键任务，请尝试另一个!
注意:此解决方案不允许字母中符号的重复，并且字母必须等于或大于输出字符串的大小，使得这种方法在某些情况下不太可取，这完全取决于您的用例。
很可怕，我知道，但我就是忍不住:
namespace ConsoleApplication2
{
using System;
using System.Text.RegularExpressions;
class Program
{
static void Main(string[] args)
{
Random adomRng = new Random();
string rndString = string.Empty;
char c;
for (int i = 0; i < 8; i++)
{
while (!Regex.IsMatch((c=Convert.ToChar(adomRng.Next(48,128))).ToString(), "[A-Za-z0-9]"));
rndString += c;
}
Console.WriteLine(rndString + Environment.NewLine);
}
}
}
我简单的一行代码为我工作:)
string random = string.Join("", Guid.NewGuid().ToString("n").Take(8).Select(o => o));
Response.Write(random.ToUpper());
Response.Write(random.ToLower());
对任意长度的字符串展开
public static string RandomString(int length)
{
//length = length < 0 ? length * -1 : length;
var str = "";
do
{
str += Guid.NewGuid().ToString().Replace("-", "");
}
while (length > str.Length);
return str.Substring(0, length);
}
对于加密和非加密，有效地:
public static string GenerateRandomString(int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890") =>
new Random().GenerateRandomString(length, charset);
public static string GenerateRandomString(this Random random, int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890") =>
RandomString(random.NextBytes, length, charset.ToCharArray());
public static string GenerateRandomCryptoString(int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
{
using (var crypto = new System.Security.Cryptography.RNGCryptoServiceProvider())
return crypto.GenerateRandomCryptoString(length, charset);
}
public static string GenerateRandomCryptoString(this RNGCryptoServiceProvider random, int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890") =>
RandomString(random.GetBytes, length, charset.ToCharArray());
private static string RandomString(Action<byte[]> fillRandomBuffer, int length, char[] charset)
{
if (length < 0)
throw new ArgumentOutOfRangeException(nameof(length), $"{nameof(length)} must be greater or equal to 0");
if (charset is null)
throw new ArgumentNullException(nameof(charset));
if (charset.Length == 0)
throw new ArgumentException($"{nameof(charset)} must contain at least 1 character", nameof(charset));
var maxIdx = charset.Length;
var chars = new char[length];
var randomBuffer = new byte[length * 4];
fillRandomBuffer(randomBuffer);
for (var i = 0; i < length; i++)
chars[i] = charset[BitConverter.ToUInt32(randomBuffer, i * 4) % maxIdx];
return new string(chars);
}
使用生成器和LINQ。不是最快的选项(特别是因为它不会一次生成所有字节)，但相当整洁和可扩展:
private static readonly Random _random = new Random();
public static string GenerateRandomString(int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890") =>
new string(_random.GetGenerator().RandomChars(charset.ToCharArray()).Take(length).ToArray());
public static string GenerateRandomCryptoString(int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
{
using (var crypto = new System.Security.Cryptography.RNGCryptoServiceProvider())
return new string(crypto.GetGenerator().RandomChars(charset.ToCharArray()).Take(length).ToArray());
}
public static IEnumerable<char> RandomChars(this Func<uint, IEnumerable<uint>> randomGenerator, char[] charset)
{
if (charset is null)
throw new ArgumentNullException(nameof(charset));
if (charset.Length == 0)
throw new ArgumentException($"{nameof(charset)} must contain at least 1 character", nameof(charset));
return randomGenerator((uint)charset.Length).Select(r => charset[r]);
}
public static Func<uint, IEnumerable<uint>> GetGenerator(this Random random)
{
if (random is null)
throw new ArgumentNullException(nameof(random));
return GeneratorFunc_Inner;
IEnumerable<uint> GeneratorFunc_Inner(uint maxValue)
{
if (maxValue > int.MaxValue)
throw new ArgumentOutOfRangeException(nameof(maxValue));
return Generator_Inner();
IEnumerable<uint> Generator_Inner()
{
var randomBytes = new byte[4];
while (true)
{
random.NextBytes(randomBytes);
yield return BitConverter.ToUInt32(randomBytes, 0) % maxValue;
}
}
}
}
public static Func<uint, IEnumerable<uint>> GetGenerator(this System.Security.Cryptography.RNGCryptoServiceProvider random)
{
if (random is null)
throw new ArgumentNullException(nameof(random));
return Generator_Inner;
IEnumerable<uint> Generator_Inner(uint maxValue)
{
var randomBytes = new byte[4];
while (true)
{
random.GetBytes(randomBytes);
yield return BitConverter.ToUInt32(randomBytes, 0) % maxValue;
}
}
}
一个更简单的版本，使用LINQ只用于非加密字符串:
private static readonly Random _random = new Random();
public static string RandomString(int length, string charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890") =>
new string(_random.GenerateChars(charset).Take(length).ToArray());
public static IEnumerable<char> GenerateChars(this Random random, string charset)
{
if (charset is null) throw new ArgumentNullException(nameof(charset));
if (charset.Length == 0) throw new ArgumentException($"{nameof(charset)} must contain at least 1 character", nameof(charset));
return random.Generator(charset.Length).Select(r => charset[r]);
}
public static IEnumerable<int> Generator(this Random random, int maxValue)
{
if (random is null) throw new ArgumentNullException(nameof(random));
return Generator_Inner();
IEnumerable<int> Generator_Inner() { while (true) yield return random.Next(maxValue); }
}
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