OracleConnection cn = new OracleConnection("user id=scott;password=tiger;data source=ganesh1");
        OracleDataAdapter da = new OracleDataAdapter("select * from emp", cn);
         ds = new DataSet();
        da.Fill(ds, "temp");
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();

  protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
    { //checking whether rowtype is datacontrolrowtype
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            double annsal;
//getting the required data from database
            annsal =double .Parse ( ds.Tables[0].Rows[e.Row.RowIndex]["sal"].ToString()) * 12;
//initializing and adding label control to gridview

            Label l1=new Label();

            l1.Text =annsal .ToString ();
            e.Row .Cells [1].Controls .Add (l1);

      //checking tha annsal and drawing the row with particular color

            if (annsal > 1000)
            {
                e.Row.BackColor = System.Drawing.Color.Red;

            }
            else
                e.Row.BackColor = System.Drawing.Color.Gray;
        }
    }