CODEWITHSUNDEEP
c#winformsbinding
Alessandro
Alessandro

Reputation: 886

Bind object to ListBox

I am doing a Windows Form Application and I have the following classes:

Person.cs

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

    public Person(string name)
    {
        this.name = name;
    }
}

Repository.cs

class Repository
{

    private static instance;

    private Repository()
    {
        persons= new List<Person>();
    }

    public static Instance
    {
        get
        {
             if (instance == null)
             {
                 instance = new Repository();
             }
             return instance;
        }
    }

    private List<Person> videos;

    public List<Person> getVideos()
    {
        return videos;
    }
}

I want to bind a ListBox in my Form to the list of persons in my repository.

How can I do that? I am trying to do that using the designer, I have the field DataSource in my ListBox, do I bind it with my Person or Repository class? The fields of the cass must be public? After the binding any data I add to my repository will automatically appear in my ListBox?

Upvotes: 0

Views: 1100

Answers (1)

TaW
TaW

Reputation: 54453

Here is an absolutely minimal example of databinding a List<T> to a ListBox:

class Person
{
    public string Name{ get; set; }               // the property we need for binding
    public Person(string name) { Name = name; }   // a constructor for convenience
    public override string ToString() {  return Name; }  // necessary to show in ListBox
}

class Repository
{
    public List<Person> persons { get; set; }
    public Repository()  { persons = new List<Person>(); }
}

private void button1_Click(object sender, EventArgs e)
{
    Repository rep = new Repository();           // set up the repository
    rep.persons.Add(new Person("Tom Jones"));    // add a value
    listBox1.DataSource = rep.persons;           // bind to a List<T>
}

Note: The display will not update on each change to the DataSource for several reasons, most notably for performance. We can control the refresh, in a minimal way like this:

private void button2_Click(object sender, EventArgs e)
{
    rep.persons.Add(new Person("Tom Riddle"));
    listBox1.DataSource = null;  
    listBox1.DataSource = rep.persons;  
}

Expanding the example a little, using a BindingSource we can, among other things, call ResetBindings to update the items shown like this:

private void button1_Click(object sender, EventArgs e)
{
    rep.persons.Add(new Person("Tom Jones"));
    rep.persons.Add(new Person("Tom Hanks"));
    BindingSource bs = new BindingSource(rep, "persons");
    listBox1.DataSource = bs;
}

private void button2_Click(object sender, EventArgs e)
{
    rep.persons.Add(new Person("Tom Riddle"));
    BindingSource bs = (BindingSource)listBox1.DataSource;
    bs.ResetBindings(false);
}

Upvotes: 1

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