title: DataGridViewRow save data when adding a new row C#
body: <p>I have a DataGridView in Win Form with 2 ComboBoxColumns bound to each other. When a user chooses a category from first combobox column, values of the second one are filtered.</p>
  
  <p>When I add the first row the code works well, but when I add new row and value of 1st combobox is different from the 1st row, child combobox of 1st row is updated and exception arises.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>      DataGridViewComboBoxColumn specCmb = new DataGridViewComboBoxColumn();
              specCmb.HeaderText = "Specification";
              specCmb.DataSource = specBndSource;
              specCmb.DisplayMember = "specName";
              dataGridView1.Columns.Add(specCmb);
              SqlDataAdapter itemAdapter = new SqlDataAdapter("SELECT ItemCode, ItemName, FrgnName, U_Index FROM dbo.OITM WHERE ItemCode LIKE 'AE%'", sqlConnection);
              itemAdapter.Fill(dataset, "DTF.dbo.OITM");
              DataRelation rel = new DataRelation("SpecItem", 
                  dataset.Tables["DTF_Medical.dbo.Specification"].Columns["specID"],
                  dataset.Tables["DTF.dbo.OITM"].Columns["U_Index"]);
              dataset.Relations.Add(rel);
  
      DataGridViewComboBoxColumn itemCodeCmb = new DataGridViewComboBoxColumn();
              BindingSource itemBndSource = new BindingSource();
              itemBndSource.DataSource = specBndSource;
              itemBndSource.DataMember = "SpecItem";
              itemCodeCmb.HeaderText = "Item Code";
              itemCodeCmb.DataSource = itemBndSource;
              itemCodeCmb.DisplayMember = "ItemCode";
              itemCodeCmb.ValueMember = "ItemCode";
              dataGridView1.Columns.Add(itemCodeCmb);
  </code></pre>
  
  <p>I need to save changes of the previous row as soon as user adds a new one. Help,please)</p>