title: How to multiply textbox with gridview columns
body: <p>I have write this code to create a gridview with 3 columns</p>
  
  <pre><code>DataTable dt = new DataTable();
  dt = new DataTable();
  dt.Columns.Add("ID", typeof(int)).AutoIncrement = true;
  dt.Columns.Add("Name", typeof(string));
  dt.Columns.Add("Price(Grouch)/Hectares", typeof(float));
  DataColumn[] keys = new DataColumn[2];
  keys[0] = dt.Columns["ID"];
  dt.PrimaryKey = keys;
  dt.Rows.Add("1", "Seaside Location", 1.5);
  
  Session[key] = dt;
  return dt;
  </code></pre>
  
  <p>I would like to add in this code a textbox with the quantity.</p>
  
  <p>When i give the quantity i want in another textbox to have the total.</p>
  
  <p>for example 2*1.5=3</p>
  
  <p>How can i do that?</p>
  
  <p>My huge problem is that i dont know how to take the values of the 3rd column.The value 1.5 in this example.</p>