Question

I want to create a random password generator in my ASP.NET C# web application.

I have created that but it is applicable only for the integer format. If I give any characters it shows the debugging error as “my input format is wrong”.

But i want to enter both string and integer. For example my textbox field may be

dft-001

I want a random password for this value and also my length should be restricted to 8 digits or characters only.

My current code:

public static string CreateRandomPassword(int PasswordLength)
    {

        string _allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789-";
        Random randNum = new Random();
        char[] chars = new char[PasswordLength];
        int allowedCharCount = _allowedChars.Length;

        for (int i = 0; i < PasswordLength; i++)
        {
            chars[i] = _allowedChars[(int)((_allowedChars.Length) * randNum.NextDouble())];
        }

        return new string(chars);
    }


protected void Button1_Click(object sender, EventArgs e)
    {
        userid.Text = "Your id is:     " + id.Text;
        if(id .Text!="")
        {

            string myInt = id.Text.ToString(); 
            password.Text = "Your password is: " + CreateRandomPassword(int.Parse(myInt)); 
        }
       }

Answer 1

There are a few things you can do to correct this based on what you have stated in your requirements.

public static string CreateRandomPassword()  //If you are always going to want 8 characters then there is no need to pass a length argument
    {
        string _allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789-";
        Random randNum = new Random((int)DateTime.Now.Ticks);  //Don't forget to seed your random, or else it won't really be random
        char[] chars = new char[8];
        //again, no need to pass this a variable if you always want 8

        for (int i = 0; i < 8; i++)
        {
            chars[i] = _allowedChars[randNum.Next(_allowedChars.Length)];
            //No need to over complicate this, passing an integer value to Random.Next will "Return a nonnegative random number less than the specified maximum."
        }
        return new string(chars);
    }


protected void Button1_Click(object sender, EventArgs e)
    {
        userid.Text = "Your id is:     " + id.Text;
        if(id .Text!="")
        {
            password.Text = "Your password is: " + CreateRandomPassword(); 
        }
    }

If I’ve understood what you want to do correctly, then this should get you there.

Ref: MSDN Random.Next