InvalidOperationException Occurs When Editing the Last Row After Previously Deleting the last Row from a DataGrid

I am having a problem when I delete the last row of a table.  The delete will work properly, but if I then edit the new last row I am getting an Invalid Operation Exception from my CurrentChanged Event Handler.   What I noticed is that when I am deleting the last record, it does the delete to the datagrid then jumps to the CurrentChanged event handler and after it finishes, it goes back and finishes the rest of the delete routine.  Why is it doing this?  Any thoughts?

    // Instantiate binding source for binding navigator
            this.m_srcCollectionHistoryType = new BindingSource();
            this.m_srcCollectionHistoryType.DataSource = this.m_dsCollectionHistory.CollectionHistoryType;

            this.grdCollectionHistoryType.AutoGenerateColumns = false;

            this.grdCollectionHistoryType.DataSource = this.m_srcCollectionHistoryType;
            this.navCollectionHistoryType.BindingSource = this.m_srcCollectionHistoryType;

this.m_srcCollectionHistoryType.CurrentChanged += new EventHandler(m_srcCollectionHistoryType_CurrentChanged);


//Event Handlers
        private void btnDeleteCollectionHistoryType_Click(object sender, EventArgs e)
        {
            DataRowView rowView =
                (DataRowView)this.grdCollectionHistoryType.CurrentRow.DataBoundItem;
            try
            {
                string currentRow = rowView["Type"].ToString();
                if (currentRow == "Unknown")
                {
                    MessageBox.Show("You cannot delete an 'Unknown'");
                    return;
                }

                rowView.Delete();      <-- Jumps to CurrentChanged event handler after executing this statement
                int recordsAffected =
                    this.m_adpCollectionHistoryType.Update(rowView.Row);
                MessageBox.Show(string.Format("Collection History Type: '{0}' deleted.", currentRow));
            }
            catch (InvalidConstraintException)
            {
                MessageBox.Show("You cannot delete a record that is linked to records in Collection History Key Table!");
            }
            catch (SqlException)
            {
                MessageBox.Show("You cannot delete this record!");
            }
        }

private void m_srcCollectionHistoryType_CurrentChanged(object sender, EventArgs e)
        {
            if (this.grdCollectionHistoryType.CurrentRow == null) return;
           
 
            if (this.grdCollectionHistoryType.CurrentRow.Index == (this.grdCollectionHistoryType.RowCount - 1))
            {
                this.grdCollectionHistoryType.DataSource = null;                     <---- Causes InvalidOperationException occurs here
                this.grdCollectionHistoryType.DataSource = m_srcCollectionHistoryType;
            }