title: Show message in empty cells in GridView
body: <p>I'm importing <code>GridView</code> from excel 
  I need to show a message near every empty cell to give the user information about what it should be writing..</p>
  
  <pre><code>void simpleButton1_Click(object sender, System.EventArgs e)
  {
      string[] msg = new string[60];
      string[] error = new string[400];
      for (int i = 0; i &lt; gridView3.RowCount ; i++)
      {
          System.Data.DataRow Rows = gridView3.GetDataRow(i);
          string cellvalue = Rows[0].ToString();
          if (cellvalue == "")
          {
              msg[0] = "Missing 'First Name'";
              error[i] = msg[0] + " - ";  
          }   
          cellvalue = Rows[1].ToString();
          if (cellvalue == "")
          {
              msg[1] = "Missing 'Last Name'";
              error[i] += msg[1] + " - ";
          }
          //...
      }
  }
  </code></pre>
  
  <p>How can I put the variable <code>msg[]</code> to the specific cell with a little image or <code>"!"</code> figure or maybe I can color the cell</p>