try
            {
                double imoney = Convert.ToDouble(this.txtimoney.Text);
                double rmoney = Convert.ToDouble(this.txtrmoney.Text);
                string times = DateTime.Now.Year.ToString() + "-" + DateTime.Now.Month.ToString() + "-" + DateTime.Now.Day.ToString();
                string sql = "insert into customertable values('" + this.ddlname.Text + "','" + this.txtclientco.Text + "','" + this.txtclientitem.Text + "'," + imoney + ",'" + this.txtclienttime.Text + "'," + rmoney + ",'" + this.txtrtime.Text + "','" + this.txtnum.Text + "','" + this.ddlxiaozu.Text + "','" + times + "')";
                SqlConnection conn = new SqlConnection(Common.connection);
                conn.Open();
                SqlCommand command = new SqlCommand(sql, conn);
                int flag = 0;
                flag = command.ExecuteNonQuery();
                string sql1 = "select count(*) from cnum where cbianhao='" + this.txtnum.Text + "'";
                SqlCommand command1 = new SqlCommand(sql1, conn);
                SqlDataReader dr1 = command1.ExecuteReader();
                int num = 0;
                if (dr1.Read())
                {
                    num = Convert.ToInt32(dr1[0]);
                    dr1.Close();
                }
                if (num <= 0)
                {
                    string sql2 = "insert into cnum values('" + txtnum.Text + "')";
                    SqlCommand command2 = new SqlCommand(sql2,conn);
                    command2.ExecuteNonQuery();
                }
                if (flag > 0)
                {
                    Response.Redirect("hit.aspx");
                }
                else
                {
                    this.ClientScript.RegisterClientScriptBlock(this.GetType(), "", "<script>alert('添加失败请重新检查不要非法操作')" + "</scirpt>");
                }
               
                conn.Close();
            }
            catch (Exception ex)
            {
                string message = ex.Message.ToString();
                Response.Write("<script language='javascript'>alert('" + message + "')" + "</script>");
            }
        }

由于代码已经过优化或者本机框架位于调用堆栈之上，无法计算表达式的值