SQLHelper的简单应用，高手绕道，写出最近用的一个类，仅供初学者参考

     为了更好的表达与应用，方便初学者的学习，在此我写出四个一般处理程序，分别实现增、删、改、查，一通百通。

增：

add.ashx:

using System.Web;
using System.Data.SqlClient;

namespace test_SQLHelper_
{
    /// <summary>
    /// Add 的摘要说明
    /// </summary>
    public class Add : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            string examsubject=context.Request["examsubject"];
            string languageclass=context.Request["languageclass"];
            SqlParameter[] para={
            new SqlParameter("@ExamSubject",examsubject),
            new SqlParameter("@LanguageClass",languageclass)
            };
           SQLHelper.ExecuteNonQuery(SQLHelper.ConnectionStrings,System.Data.CommandType.Text,"insert into T_ExamCalendar (ExamSubject,LanguageClass) values(@ExamSubject,@LanguageClass)",para);
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

删：

delete.ashx:

using System.Web;
using System.Data.SqlClient;

namespace test_SQLHelper_
{
    /// <summary>
    /// delete 的摘要说明
    /// </summary>
    public class delete : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            string examsubject = context.Request["examsubject"];
            SqlParameter[] pare = {
                                  new SqlParameter ("@ExamSubject",examsubject)
                                  };
            SQLHelper.ExecuteNonQuery(SQLHelper.ConnectionStrings,System.Data.CommandType.Text,"delete from T_ExamCalendar where ExamSubject=@ExamSubject",pare);
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

改：

update.ashx:

using System.Web;
using System.Data.SqlClient;

namespace test_SQLHelper_
{
    /// <summary>
    /// update 的摘要说明
    /// </summary>
    public class update : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            string examsubject = context.Request["examsubject"];
            string examaccuratetime = context.Request["examaccuratetime"];
            SqlParameter[] para = {
                                new SqlParameter ("@ExamSubject",examsubject),
                                new SqlParameter("@ExamAccurateTime",examaccuratetime)
                                };
            SQLHelper.ExecuteNonQuery(SQLHelper.ConnectionStrings,System.Data.CommandType.Text,"update T_ExamCalendar set ExamAccurateTime=@ExamAccurateTime where ExamSubject=@ExamSubject",para);
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

查：

check.ashx:

using System.Collections.Generic;
using System.Web;
using System.Data;
using System.Web.Script.Serialization;

namespace test_SQLHelper_
{
    /// <summary>
    /// check 的摘要说明
    /// </summary>
    public class check : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            DataTable dt = new DataTable();
            dt = SQLHelper.ExecuteDataTable(SQLHelper.ConnectionStrings, System.Data.CommandType.Text, "select * from T_ExamCalendar");
            List<Dictionary<string, string>> List = new List<Dictionary<string, string>>();
            for (int i = 0; i < dt.Rows.Count;i++ ) {
                var Dic = new Dictionary<string, string> {
                {"ExamSubject",dt.Rows[i]["ExamSubject"].ToString()},
                {"LanguageClass",dt.Rows[i]["LanguageClass"].ToString()}
                };
                List.Add(Dic);
            }
            JavaScriptSerializer jss = new JavaScriptSerializer();
            context.Response.Write(jss.Serialize(List));
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

      使用的连接字符串为：（写成SQLHelper的一个字段）

public static readonly string ConnectionStrings = ConfigurationManager.ConnectionStrings["ConnectionStrings"].ConnectionString;

      于是每次都如此调用，如上：Check.ashx中的（粗体部分为链接字符串，写在web.config中）

dt = SQLHelper.ExecuteDataTable(SQLHelper.ConnectionStrings, System.Data.CommandType.Text, "select * from T_ExamCalendar");

     web.config中的链接字符串如下：

<connectionStrings>
  <add name="ConnectionStrings" connectionString="server=CHENSHENGTAI-PC;database=EXAMCALENDAR.MDF;Integrated Security=True;" providerName="System.Data.SqlClient" />
 </connectionStrings>