how to display date data in text box using data grid view

See more:

C#3.0

.NET3.5

C#

.NET

i have created a form in which there is 1 label starting date along with respective textbox.i have inserted the value in the database through ADD button (using insert query).I have taken datagrid view to display the data .The problem is now i want that when i select one row of datagridview then it should display data in respective textbox. i have tried following code but not able to get desired result for date field

private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
      {
          SqlConnection con = new SqlConnection("Data Source=SW-PC-20;Initial Catalog=PSM;Integrated Security=True");
          con.Open();

          SqlCommand com = new SqlCommand("select * from Publicity_Threshold  where Threshold_id=@Threshold_id='" + dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString() + "'", con);
          SqlDataReader dr = com.ExecuteReader();
          if (dr.HasRows)
          {
              dr.Read();
              txtThresholdID.Text = dr[0].ToString();
              cboThreholdname.Text = dr[1].ToString();
              cbomethodid.Text = dr[2].ToString();
              cbomediaused.Text = dr[3].ToString();
             startingdate.Value = dr[4].ToString();                    }
          dr.Close();
          con.Close();
      }

error is in this only
startingdate.Value = dr[4].ToString();
can u rectify me