"BindingSource cannot be its own data source" - error when trying to reset the binding source from a method in another class

We are binding a DataGridview using BindingSource. So in the main thread we have given like this.

            class1BindingSource = new BindingSource();
            class1BindingSource.DataSource = class1List;  
            this.dataGridView1.DataSource = class1BindingSource;

After that i have a placed a background worker in the form and is triggering in a button click.

i.e. in the button click

this.backgroundWorker1.RunWorkerAsync()

In the BackgroundWorker DoWork Event i am trying to update the BindingSource and there by trying to update the DataGridview.

So the BindingSource reset is done in a method in another class.

DoWork Event

Class2 cl2 = new Class2();
cl2.UpdateBindingSource(class1BindingSource);

UpdateBindingSource Method

public void UpdateBindingSource(BindingSource bs)
        {
            Class1 c1 = bs.Current as Class1;    
            for (int i = 0; i < 1000; i++)
            {
                lock (bs.SyncRoot)
                {
                    c1.MyProperty1 = i;
                    bs.ResetItem(0);
                }
            }
        }

Now i am getting an exception like BindingSource cannot be its own data source. Do not set the DataSource and DataMember properties to values that refer back to BindingSource.

If i am doing this in my DoWork Event then i can reset the item in the control thread itself using BeginInvoke method.

But actually i am trying to simulate our application scenario. So i want to solve this in this format.

Can any one help me on this.