title: Add a new row in bounded dataGridView on button click
body: <p>I have a datagridview and filling it using datatable as datasource .</p>
  
  <p>I want to add a new row on button click , using method to first unbound it and then add new row in it . As the following :  </p>
  
  <pre><code> dataGridView1.AutoGenerateColumns = false; 
   dataGridView1.DataSource= null;
   dataGridView1.Rows.Add();
  </code></pre>
  
  <p>But instead of adding new row below the existing row , it clears the existing data in row. I think present that row as new row. </p>
  
  <p>how can I add the new row below the existing row and keep the data in other rows safe . </p>
  
  <p>NOTE -- columns of datagridview view are custom columns  .</p>