Question

I have a System.Timers.Timer that updates my win form application components in every 5 seconds.

I have a comboBox and global IEnumerable<Person> list that updated also in everty 5 seconds.
I need to add persons name to combobox. If the name is already in the list, i should not add.

How can I proceed?
Here is the code inside the timer event. This adds multiple times and i am not sure to do that with foreach, maybe IEnumareble interface has an easier way.

foreach (Persons person in personsList)
{
  comboBox.Items.Add(person.Name);
}

Answer 1

This is one of the simpler solutions to this problem, assuming you’re using .NET 3.5 or greater:

foreach(Person person in personsList)
{
    if(!comboBox.Items.Cast<string>().Contains(person.Name)) 
    {
        comboBox.Items.Add(person.Name);
    }
}

If you’re using 3.0 or earlier, you’ll have to do the search yourself:

foreach(Person person in personsList)
{
    bool contains = false;

    foreach(string item in comboBox.Items)
    {
        contains = string.Equals(item, person.Name);

        if(contains) break;
    }

    if(!contains) comboBox.Items.Add(person.Name);
}