how to assign a particular column values retrieve using data reader and data table ?

if (dr.HasRows)
               {
                   if (dr.Read())
                   {
                       if (dt.Rows[0][0].ToString() == String.Empty)
                       {
                           textBox1.Text = null;
                       }
                       else
                       {
                           textBox1.Text = dt.Rows[0][0].ToString();
                       }
                       if (dt.Rows[1][0].ToString() == String.Empty)
                       {
                           textBox2.Text = null;
                       }
                       else
                       {
                           textBox2.Text = dt.Rows[1][0].ToString();
                       }
                       if (dt.Rows[2][0].ToString() == String.Empty)
                       {
                           textBox3.Text = null;
                       }
                       else
                       {etc.

in database there is only two row in column

and show error on third 


i just want to compare bland or null value an d i don't know how to do this