[ASP.NET] Inserir e Update

try
                {
                    foreach (GridViewRow row in GridView1.Rows)
                    {
                        if (row.RowType == DataControlRowType.DataRow)
                        {
                            CheckBox chkRow = (row.Cells[0].FindControl("CheckBox1") as CheckBox);
                            if (chkRow.Checked)
                            {
                                int Id = Convert.ToInt32(GridView1.DataKeys[row.RowIndex].Value.ToString());
                                SqlCommand cmd = new SqlCommand("UPDATE dbo.registo SET nome='" + txtNome.Text + "',apelido='" + txtApelido.Text + "',titulo='" + txtTitulo.Text + "',cidade='" + txtCidade.Text + "',pais='" + txtPais.Text + "',Imagem='" + "~/imagens/" + FileUpload1.FileName + "' WHERE Id=@id", conn);

                                cmd.Parameters.Add("@Id", SqlDbType.Int).Value = Id.ToString();
                                cmd.ExecuteNonQuery();
                                Response.Redirect("Main.aspx");
                            }
                        }
                    }

                }
                catch
                {
                    comm.CommandType = System.Data.CommandType.Text;
                    comm.CommandText = "INSERT INTO Registo(Id,Nome,Apelido,Titulo,Cidade,Pais,Imagem) VALUES ('" + id + "','" + txtNome.Text + "','" + txtApelido.Text + "','" + txtTitulo.Text + "','" + txtCidade.Text + "','" + txtPais.Text + "','" + local.ToString() + "')";

                    comm.ExecuteNonQuery();
                    Atualizar();
                    Response.Redirect("Main.aspx");
                }