String was not recognized as a valid DateTime

Question

Hi!

Someone to help me for this ; I have the following code in my project:

public void LoadRecords()
       {
           int i = 0;
           dataGridView1.Rows.Clear();
           cn.Open();
           cm = new OleDbCommand("select * from Produit", cn);
           dr = cm.ExecuteReader();
           while (dr.Read())
           {
               i += 1;
               dataGridView1.Rows.Add(i, dr["ProdID"].ToString(), dr["nom"].ToString(), dr["Quantite"].ToString(), dr["peremption"].ToString());

               foreach (DataGridViewRow row in dataGridView1.Rows)
               {


                   var now = DateTime.npw;

                   var expireDate = DateTime.Parse(row.Cells[3].Value.ToString());
                   var sixtyDayBefore = expireDate.AddDays(-1);
                   if(now > sixtyDayBefore && now > expireDate)
                   {
                       row.DefaultCellStyle.BackColor = Color.Yellow;

                   }
                   else if(now > expireDate)
                   {
                       row.DefaultCellStyle.BackColor = Color.Red;
                   }
               }

           }

               cn.Close();
           dr.Close();
       }