Create random string in C#

To generate random alphanumeric strings in C#, you can use the Random class along with a string containing all the possible characters you want to include. Here's an example that generates a random string of length 10:

using System;
using System.Linq;

class Program
{
    static void Main()
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        var random = new Random();
        var result = new string(
            Enumerable.Repeat(chars, 10)
                      .Select(s => s[random.Next(s.Length)])
                      .ToArray());
        Console.WriteLine(result);
    }
}

To generate secure random alphanumeric strings, you should use the RNGCryptoServiceProvider class from the System.Security.Cryptography namespace. Here's an example that generates a secure random string of length 10:

using System;
using System.Linq;
using System.Security.Cryptography;

class Program
{
    static void Main()
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        var random = new RNGCryptoServiceProvider();
        var result = new string(
            Enumerable.Range(1, 10)
                      .Select(_ => {
                          var bytes = new byte[1];
                          random.GetBytes(bytes);
                          var charIndex = (bytes[0] % chars.Length);
                          return chars[charIndex];
                      })
                      .ToArray());
        Console.WriteLine(result);
    }
}

Note that the RNGCryptoServiceProvider class is slower than the Random class, but provides much stronger security guarantees.

Generate random string in C#:

using System;

class Program
{
    static void Main()
    {
        string randomString = GenerateRandomString(10);
        Console.WriteLine(randomString);
    }

    static string GenerateRandomString(int length)
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        Random random = new Random();
        return new string(Enumerable.Repeat(chars, length)
            .Select(s => s[random.Next(s.Length)]).ToArray());
    }
}

Random string generation using Guid in C#:

string randomString = Guid.NewGuid().ToString("N").Substring(0, 10);

Random string with uppercase and lowercase characters in C#:

string randomString = Path.GetRandomFileName().Replace(".", "").Substring(0, 10);

Random string with numbers in C#:

string randomString = Guid.NewGuid().ToString("N").Substring(0, 10);

C# random string with special characters:

const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()-_+=<>?";
string randomString = new string(Enumerable.Repeat(chars, 10)
    .Select(s => s[random.Next(s.Length)]).ToArray());