CODEWITHSUNDEEP
c#stringwinformslistrandom
Tibia Player
Tibia Player

Reputation: 13

Randomize string and add to listbox

I'm having trouble randomizing X-amounts of strings and adding them to my listbox. it keeps adding the same string over and over. i want it to add 1 line per string. if i say that amount is 11, it just makes one string and adds it 11 times to listbox. what am i doing wrong?

here is my code:

for (int i = 0; i < amount; i++)
        {

            Random adomRng = new Random();
            string rndString = string.Empty;
            char c;

            for (int t = 0; t < 8; t++)
            {
                while (!Regex.IsMatch((c = Convert.ToChar(adomRng.Next(48, 128))).ToString(), "[a-z0-9]")) ;
                rndString += c;
            }

            listBox1.Items.Add(rndString);
        }

Upvotes: 0

Views: 222

Answers (2)

Kien Chu
Kien Chu

Reputation: 4895

Random adomRng = new Random();
for (int i = 0; i < amount; i++)
{
    string rndString = string.Empty;
    char c;
    for (int t = 0; t < 8; t++)
    {
        while (!Regex.IsMatch((c = Convert.ToChar(adomRng.Next(48, 128))).ToString(), "[a-z0-9]")) ;
        rndString += c;
    }
    listBox1.Items.Add(rndString);
}

Put the random init code outside of the loop, it will get you the correct result

Explanation: creating multiple new random objects in the short period of time (let's say inside a for loop) will always give you the same output because it will use the current timestamp as random seed.

Upvotes: 2

sujith karivelil
sujith karivelil

Reputation: 29026

You are almost there,just make two simple changes in your code to achieve the target:

for (int t = 0; t < 8; t++)
 {
   rndString =""; //Change 1
   while (!Regex.IsMatch((c = Convert.ToChar(adomRng.Next(48, 128))).ToString(), "[a-z0-9]")) ;
   rndString += c;
   listBox1.Items.Add(rndString);// change  2
 }

Upvotes: 0

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