Binding List<T> to DataGridView in WinForm

List does not implement IBindingList so the grid does not know about your new items.

Bind your DataGridView to a BindingList<T> instead.

var list = new BindingList<Person>(persons);
myGrid.DataSource = list;

But I would even go further and bind your grid to a BindingSource

var list = new List<Person>()
{
    new Person { Name = "Joe", },
    new Person { Name = "Misha", },
};
var bindingList = new BindingList<Person>(list);
var source = new BindingSource(bindingList, null);
grid.DataSource = source;

Every time you add a new element to the List you need to re-bind your Grid. Something like:

List<Person> persons = new List<Person>();
persons.Add(new Person() { Name = "Joe", Surname = "Black" });
persons.Add(new Person() { Name = "Misha", Surname = "Kozlov" });
dataGridView1.DataSource = persons;

// added a new item
persons.Add(new Person() { Name = "John", Surname = "Doe" });
// bind to the updated source
dataGridView1.DataSource = persons;

Yes, it is possible to do with out rebinding by implementing INotifyPropertyChanged Interface.

Pretty Simple example is available here,

http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged.aspx