ADO.NET Execute SQL

SqlConnection myConnection = new SqlConnection(Environment.GetEnvironmentVariable("SqlDbConnectionString"));
myConnection.Open();

SqlCommand myCommand = new SqlCommand();
myCommand.Connection = myConnection;
myCommand.CommandText = "UPDATE tblTable01 SET IsEmailSent=1 WHERE Id = " + dtList.Rows[i][""];
myCommand.ExecuteNonQuery();

myConnection.Close();