title: How to add sum of columns in datagridview with datasource
body: <p>How would i add a a row to the bottom of this datagridview with a sum all the above rows. The rows are bound from a datatable.</p>
  
  <pre><code>DataGridView1.DataSource = DT;
  for (int i = 0; i &lt; DataGridView1.Rows.Count; ++i)
  {
      sum += Convert.ToInt32(DataGridView1.Rows[i].Cells[col].Value);
      DataGridView1.Rows.Insert(sum);
  }
  </code></pre>
  
  <p>I have tried to ;ppl at DataGridView1.Rows.Insert and .Add but am unsure how i would be best to do this.</p>