(原)ASP.NET中的单引号和双引号
最近做的一个仓库管理(OA)系统遇到的问题
我需要使用下拉菜单读取数据库整条的记录,进行运算,代码如下.但是运行老是出错.找了一天时间才找出错误,少了一对单引号
<%@ Page Language="C#" AutoEventWireup="true" EnableSessionState="True" CodeFile="test.aspx.cs" Inherits="Web_test" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" ><head id="Head1" runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div> <asp:Label ID="info11" runat="server" Text="Label"></asp:Label> <asp:DropDownList ID="L_GoodsName" runat="server" DataTextField="info2" DataValueField="info_id" Width="197px" AutoPostBack="True" OnSelectedIndexChanged="L_GoodsName_SelectedIndexChanged" DataSourceID="SqlDataSource1" AppendDataBoundItems="true"> <asp:ListItem Value="" Selected="True">==请选择==</asp:ListItem> </asp:DropDownList> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> </div> <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>"></asp:SqlDataSource> </form></body></html>using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Data.SqlClient;public partial class Web_test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//if (!IsPostBack) //{ SqlDataSource1.SelectCommand = "SELECT * FROM [r_ware] ORDER BY [info_id] DESC"; //选择商品菜单 string num = GetNum(); this.info11.Text = num; GetNum(); //} //================== //存放信息 //Application["UserNameID"]="1000"; //读取信息 //String TextBox1= Application["UserNameID"].ToString();
} protected void L_GoodsName_SelectedIndexChanged(object sender, EventArgs e) { string info_id = L_GoodsName.SelectedValue;//获得此商品的ID SqlConnection conn = new SqlConnection(ConfigurationManager.AppSettings["DBConnectionString"]); conn.Open(); SqlCommand cmd = new SqlCommand("select * from r_ware where info_id = " + info_id + " ", conn); SqlDataReader my = cmd.ExecuteReader(); if (my.Read()) { TextBox1.Text = my["info7"].ToString(); TextBox2.Text = my["info10"].ToString(); // L_GoodsSum.Text = my["info"].ToString(); } my.Close(); //Response.Write(((DropDownList)sender).SelectedItem); } public String GetNum() { Application["id"] = L_GoodsName.SelectedValue; string id = Application["id"].ToString(); String Result = null; SqlConnection conn = new SqlConnection(ConfigurationManager.AppSettings["DBConnectionString"]); conn.Open(); SqlCommand cmd = new SqlCommand("select info7*info10 from r_ware where info_id = " + id + " ", conn); SqlDataReader my = cmd.ExecuteReader(); if (my.HasRows) { if (my.Read()) { Result = my[0].ToString(); } } conn.Close(); return Result; } protected void Button1_Click(object sender, EventArgs e) { }
}改.CS中的代码
"select info7*info10 from r_ware where info_id = '" + id + "' "
这里需要多一对单引号。。。到处测试成功 之前请教了网上好多人和公司的同事都没找到解决 看来今天又多学了东西 回去再看看书本吧 ^0^
