Generate random password of specified length with 
  - Special characters   
  - Number
  - Lowecase
  - Uppercase

  public static string CreatePassword(int length = 12)
    {
        const string lower = "abcdefghijklmnopqrstuvwxyz";
        const string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        const string number = "1234567890";
        const string special = "!@#$%^&*";

        var middle = length / 2;
        StringBuilder res = new StringBuilder();
        Random rnd = new Random();
        while (0 < length--)
        {
            if (middle == length)
            {
                res.Append(number[rnd.Next(number.Length)]);
            }
            else if (middle - 1 == length)
            {
                res.Append(special[rnd.Next(special.Length)]);
            }
            else
            {
                if (length % 2 == 0)
                {
                    res.Append(lower[rnd.Next(lower.Length)]);
                }
                else
                {
                    res.Append(upper[rnd.Next(upper.Length)]);
                }
            }
        }
        return res.ToString();
    }

我喜欢生成密码，就像生成软件密钥一样。您应该从遵循良好实践的字符数组中进行选择。采用@Radu094回答的内容并修改它以遵循良好的实践。不要把每个字母都放在字符数组中。有些信在电话里更难读懂。

您还应该考虑对生成的密码使用校验和，以确保它是由您生成的。实现这一点的一个好方法是使用LUHN算法。

对于这种类型的密码，我倾向于使用可能生成更容易“使用”的密码的系统。短的，通常由发音片段和一些数字组成，并且没有字符间的歧义(这是0还是O?是1还是I?)类似的

string[] words = { 'bur', 'ler', 'meh', 'ree' };
string word = "";

Random rnd = new Random();
for (i = 0; i < 3; i++)
   word += words[rnd.Next(words.length)]

int numbCount = rnd.Next(4);
for (i = 0; i < numbCount; i++)
  word += (2 + rnd.Next(7)).ToString();

return word;

(直接在浏览器中输入，因此仅作为参考。同时，要多加单词)。

插入一个定时器:timer1, 2个按钮:button1, button2, 1个textBox: textBox1，和一个comboBox: comboBox1。请务必申报:

int count = 0;

源代码:

 private void button1_Click(object sender, EventArgs e)
    {
    // This clears the textBox, resets the count, and starts the timer
        count = 0;
        textBox1.Clear();
        timer1.Start();
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
    // This generates the password, and types it in the textBox
        count += 1;
            string possible = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
            string psw = "";
            Random rnd = new Random { };
            psw += possible[rnd.Next(possible.Length)];
            textBox1.Text += psw;
            if (count == (comboBox1.SelectedIndex + 1))
            {
                timer1.Stop();
            }
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        // This adds password lengths to the comboBox to choose from.
        comboBox1.Items.Add("1");
        comboBox1.Items.Add("2");
        comboBox1.Items.Add("3");
        comboBox1.Items.Add("4");
        comboBox1.Items.Add("5");
        comboBox1.Items.Add("6");
        comboBox1.Items.Add("7");
        comboBox1.Items.Add("8");
        comboBox1.Items.Add("9");
        comboBox1.Items.Add("10");
        comboBox1.Items.Add("11");
        comboBox1.Items.Add("12");
    }
    private void button2_click(object sender, EventArgs e)
    {
        // This encrypts the password
        tochar = textBox1.Text;
        textBox1.Clear();
        char[] carray = tochar.ToCharArray();
        for (int i = 0; i < carray.Length; i++)
        {
            int num = Convert.ToInt32(carray[i]) + 10;
            string cvrt = Convert.ToChar(num).ToString();
            textBox1.Text += cvrt;
        }
    }

public static string GeneratePassword(int passLength) {
        var chars = "abcdefghijklmnopqrstuvwxyz@#$&ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        var random = new Random();
        var result = new string(
            Enumerable.Repeat(chars, passLength)
                      .Select(s => s[random.Next(s.Length)])
                      .ToArray());
        return result;
    }

public string CreatePassword(int length)
{
        const string valid = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        StringBuilder res = new StringBuilder();
        Random rnd = new Random();
        while (0 < length--)
        {
            res.Append(valid[rnd.Next(valid.Length)]);
        }
        return res.ToString();
}

这有一个很好的好处，可以从可用的字符列表中选择生成的密码(例如，仅数字，仅大写或仅小写等)。