Choose random item from a list object

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Hi,

I am playing around with Lists and I was wondering how to show a random item/element from that List.

I have a class called Person

public class Person
    {
        public string Name { get; set; }
        public string Surname { get; set; }
    }

In my form I have created two textboxes (txtName & txtSurname) what I want to achieve is whenever user clicks a button (btnShow) it will automatically display either the name or the surname (never both).

I have created a List that hold the Person Object and initialized Person object.

C#

private List<Person> people = new List();
private Person person;

This is my btnCreate event. Which adds new people to the list:

C#

private void btnShow_Click(object sender, EventArgs e){
person= new Person();
person.Name= txtName.Text;
country.Surname= txtSurname.Text;
countries.Add(country);
}

What I have tried:

This is my btnShow event which will show the List<> items in the text boxes. Keep in my mind that I want to also display only the name or surname each time not both. And I am not sure how to do it. I have tried to just simply shuffle through the whole list to get something displayed but it displayed for example, System.Random instead of actual name.

C#

private void btnShow_Click(object sender, EventArgs e){
Random r = new Random();
string random = people[r.Next(people.Count)].ToString();

txtName.Text = random.ToString();
}

Any help would be appreciated

Thanks.

Posted 30-Oct-17 8:53am

fellanmorgh

Updated 8-Nov-17 6:40am

Sean Ewington

v5

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OriginalGriff 30-Oct-17 15:14pm

Help with what, exactly?
What does the code do that you didn't expect, or not do that you did?
Where are you stuck?
What help do you need?

1 solution

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F-ES Sitecore · Accepted Answer · 2017-10-30T09:30:00

"Doesn't work" doesn't give anyone enough information to help you, what is happening that you didn't expect to happen, or what isn't happening that you want to happen?

I'm going to assume your issue is partly in using ToString on the Person object. If you don't override ToString you'll just get the name of the type. So either be explicit in how you want the result to look;

string random = people[r.Next(people.Count)];
string result = random.Surname + ", " + random.Name;

or override ToString on the Person class to return the result you want. If the result has to be random Name or Surname you can do something like

public string ToString(Random random)
{
    if (random.Next(2) == 0)
    {
        return this.Name;
    }
    else
    {
        return this.Surname;
    }
}

public override string ToString()
{
    return ToString(new Random());
}

I've done a standard ToString() and also one where you can pass in your own instance of Random. This is in case you want to run the code in a loop. Random uses the time as a seed for its random number generator so if you create new instances of Random in a loop you can end up with the same random number each time because enough time hasn't passed to generate a new seed\sequence.