display records from ms access database to c# datagridview using dateTimePicker

string strConn = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:/Users/ EmployeeAttendanceRegister.accdb";
            using (var cn = new OleDbConnection(strConn))
            {
                cn.Open();
                using (var cmd = new OleDbCommand("SELECT Username FROM SignInTime WHERE SignIn =@SignIn", cn)) 
                {
                    cmd.Parameters.Add(new OleDbParameter("@SignIn",dateTimePicker1.Value.ToShortDateString()));
using (OleDbDataAdapter oda = new OleDbDataAdapter(cmd))
                        oda.Fill(dt);
                    dataGridView1.DataSource = dt.Tables[0];
                }
            }