C# WPF Random ListBox - Remove object from one list box and add to another using a random

Question

I am using a basic WPF application. In it I have a list of Persons with a few properties. When I run the application it populates a listbox with the Persons. I have a button to random an Persons based off of a selection(1-5). When this happens, I need to remove that Person/s and move him/her to another list box I have.

I get an error while in the first foreach loop. Not sure how to loop through the personListBox. Also need to move the person from personListBox1 to personListBox2.

I need the person removed from the 1st list so that when it loops again, it will not be there to be selected again. I plan on doing something with only the second list of persons. Thanks in advance guys.

Below is the random button I am trying this with.

private void randomButton_Click(object sender, RoutedEventArgs e)
    {
        if (this.numberComboBox.SelectedIndex != -1)
        {
            List<Person> personList = new List<Person>();                
            int number = Convert.ToInt16(this.numberComboBox.SelectedItem);

            // Add each person from the one list box to the other.
            foreach (Person P in this.personListBox.Items)
            {
                personList.Add(P);
            }

            // Loop the the selected number of times to remove and add from list to list.
            for (int i = 0; i < number; i++)
            {
                int randomValue = random.Next(personListBox.Items.Count);                    
                // Need to remove the person from personListBox1 here
                // Then move them to personListBox2
            }
        } 
        else
        {
            MessageBox.Show("Please select a number before trying to random.");
        }
    }

Answer 1

Maybe this?

    private void randomButton_Click(object sender, RoutedEventArgs e)
    {
        if (this.numberComboBox.SelectedIndex != -1 && Convert.ToInt16(this.numberComboBox.SelectedItem) <= personListBox.Items.Count)
        {               
            int number = Convert.ToInt16(this.numberComboBox.SelectedItem);

            for (int i = 0; i < number; i++)
            {
                int randomValue = random.Next(personListBox.Items.Count);                    
                var person =  personListBox.Items[randomValue];
                personListBox.Items.RemoveAt(randomValue);
                personListBox2.Items.Add(person);
            }
        } 
        else
        {
            MessageBox.Show("Please select a number before trying to random.");
        }
   }

Note that i added a condition to check that the chosen number is not greater than the number of persons in the first list.

Answer 2

Check this out.

<Grid>
    <StackPanel>
        <StackPanel Orientation="Horizontal">
            <ListBox x:Name="ListBox1" DisplayMemberPath="Name"/>
            <ListBox x:Name="ListBox2" DisplayMemberPath="Name"/>
        </StackPanel>
        <Button x:Name="Button" Content="Remove" Click="Button_OnClick"></Button>
    </StackPanel>

</Grid>

public partial class Window1 : Window
{
    private ObservableCollection<Person> list1;
    private ObservableCollection<Person> list2;

    public Window1()
    {
        InitializeComponent();
        list1 = new ObservableCollection<Person>()
        {
            new Person() {Name = "NAme1"},
            new Person() {Name = "NAme2"},
            new Person() {Name = "NAme3"},
            new Person() {Name = "NAme4"},
            new Person() {Name = "NAme5"},

        };

        ListBox1.ItemsSource = list1;

        list2 = new ObservableCollection<Person>();
        ListBox2.ItemsSource = list2;
    }

    private void Button_OnClick(object sender, RoutedEventArgs e)
    {
        list2.Add(ListBox1.SelectedItem as Person);
        list1.Remove(ListBox1.SelectedItem as Person);
    }
}

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