using System.Data.SqlClient;的真实含义?

using System; using System.Collections; using System.Configuration; using System.Data; using System.using System;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using 关于c# using systemusing System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms; using System.Data.SqlClient;的真实含义? using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; usi 有无语法错误,帮我改改谢谢using System;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using Sys c#高手看看什么问题 using System; using System.Collections.Generic; using System.ComponentModel; usiusing System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System 摄氏温度和华氏温度之间的转换.using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace _11_1{public partial 求0-100所有的质数用c#编写using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;namespace WindowsApplication2{ public partial class For using System; using System.Data; using System.Configuration; using System.Linq; using System.Web; u提示“system”中不存在类型或命名空间名称‘Ling’（缺少程序集引用吗?） 遇到难题了我用C#（+EmguCV+OpenCV）调用matlaB写的小波分解函数 但是不成功 有错误 代码如下：using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Tex using System; using System.Collections.Generic; using System.Linq; using System.Text; using System. Imports System.Data.SqlClient using System.Data.Linq.SqlClient;为什么不能引用?我想用SqlMethods.Like这个方法，但是在引用using System.Data.Linq.SqlClient;头文件时~没有找到这个头文件！ 系统报错：嵌入的语句不能是声明或标记语句SqlConnection下有波浪线提示“嵌入的语句不能是声明或标记语句”代码如下：using System;using System.Data;using System.Configuration;using System.Collections;using S using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Cons using System.Linq using System; using System.Collections.Generic; using System.Windows.Forms; namespace gxz { static using System;using System.Collections.Generic;using System.Windows.Forms;namespace gxz{static class Program{/// /// 应用程序的主入口点./// [ST c_sharp中using system.linq表示什么?