protected void Button1_Click(object sender, EventArgs e)
    {
        if (CeShi())//这是测试下输入的是否正确
        {
            if (txtDatabaseName.Text.Trim()=="kj249")
            {
                try
                {
                    string name=DbSqlHelper.kj249();//这个是dbsqlhelp帮助类里方法、返回连接字符串
                    if (name != null&&name!="")
                    {
                        Session["Name"] = "kj249";
                        lblShow.Text = string.Format("<span style=color:Red;font-size:20px>数据库切换成功</span>");
                        Response.Redirect("setup.aspx");
                    }
                }
                catch (Exception ex)
                {
                    lblShow.Text = string.Format("<span style=color:Red;font-size:20px>数据库切换失败</span>");
                    lblSql.Text = ex.Message;
                }
            }
            else
            {
                try
                {
                    string name=DbSqlHelper.boram_web();
                    if (name != null && name != "")
                    {
                        Session["Name"] = "boram";
                        lblShow.Text = string.Format("<span style=color:Red;font-size:20px>数据库切换成功</span>");
                        Response.Redirect("index.aspx");
                    }
                }
                catch (Exception ex)
                {
                    lblShow.Text = string.Format("<span style=color:Red;font-size:20px>数据库切换失败</span>");
                    lblSql.Text = ex.Message;
                }
            }

 public class DbSqlHelper
  {
      protected static string connectionString = ConfigurationManager.ConnectionStrings["boram_web"].ConnectionString;
      public static string boram_web()
      {
          connectionString = ConfigurationManager.ConnectionStrings["boram_web"].ConnectionString;
          return connectionString;
      }
      public static string kj249()
      {
          connectionString = ConfigurationManager.ConnectionStrings["kj249"].ConnectionString;
          return connectionString;
      }

public class Handler : IHttpHandler {
    CollieryBll bll = new CollieryBll();
    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";
        string name = context.Request["Name"];
        if (name == null)
        {
            context.Response.Write(JsonTree().ToString());
        }
        else if (name == "kj249")
        {
            context.Response.Write(Tree249().ToString());
        }
        else
        {
            context.Response.Write(JsonTree().ToString());
        }
    }