Hi Morten,

Thank-you for the reply; I was going to add this code before, and then
saw your reply.  It's code I downloaded from a URL referenced in MSDN,
and as you'll see, the code does implement IBindingList, but the
constructor is completely empty.  It sets a private type field that's
later used in the IBindingList.AddNew() implemented function:

public class MyCollection : ArrayList, IBindingList, ITypedList
{
 private Type finalType = typeof(MyData);

 public MyCollection() {  }

 bool IBindingList.AllowNew
 {
  get { return true ; }
 }
 object IBindingList.AddNew()
 {
   return finalType.GetConstructor(new Type[]{}).Invoke(null);
 }
 // Additional implementation of IBindingList
}

public class FakeData
{
 private FakeData(){}
 public static MyCollection GetData()
 {
   MyCollection collection = new MyCollection();
   for (int i = 0; i < 10; i++)
   {
     MyData ii = new MyData();
     ii.ID = i;
     ii.FirstName = "aaa" + i.ToString();
     ii.LastName = "bbb" + i.ToString();
     collection.Add(ii);
   }
  return collection;
 }
}

public class MyData
{
 private int id = 0;
 private string firstName = null;
 private string lastName = null;

 public MyData() {}
 public int ID
 {
  get{ return id; }
  set{ id = value; }
 }
 public string FirstName
 {
  get{ return firstName; }
  set{ firstName = value; }
 }
 public string LastName
 {
   get{ return lastName; }
   set{ lastName = value; }
 }
}

public class Form1 : System.Windows.Forms.Form
{
 private System.Windows.Forms.DataGrid dataGrid1;
 private DataGridView dataGrid1;
 private DataGridView dataGrid2;

 BindingList<MyData> arrList2 = new BindingList<MyData>();
 MyData myData1 = new MyData();

 public Form1()
 {
   InitializeComponent();
   myData1.ID = 1;
   myData1.FirstName = "ccc";
   myData1.LastName = "cccc";
   arrList2.Add(myData1);

   dataGrid1.DataSource = FakeData.GetData();
   dataGrid2.DataSource = arrList2;
 }
}

Even though MyCollection implements IBindingList, the
IBindingList.AddNew() never gets called because dataGrid1 doesn't show
the new empty row, while dataGrid2 does.

MyCollection appears to also implement ITypedList, although I haven't
made heads or tails of what's all involved there yet.

So is dataGrid1 basically just binding to an ArrayList here?

On Jan 7, 1:32 am, Morten Wennevik [C# MVP]
<MortenWenne...@hotmail.com> wrote: