.NET编程小知识点（更新中...）

①Load()方法将查询出来的DataReader加载到调用它的字符串中

 

②

SqlDataReader sdr = cmd.ExecuteReader();  //返回一个DataReader类型

SqlDataReader sdr = cmd.ExecuteReader();  //返回一个DataReader类型

 

③用using关联释放资源（sdr释放资源的时候conn也会释放资源）

using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))//返回一个DataReader类型
{
     dt.Load(sdr);//Load()方法将查询出来的DataReader加载到调用它的字符串中
}

using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))//返回一个DataReader类型
{
    dt.Load(sdr);//Load()方法将查询出来的DataReader加载到调用它的字符串中
} 

 

④数据库改密码在Web/Web.Config中改

/* 待补充... */

/* 待补充... */

 

⑤原本Insert语句：insert into category (name) values('ttt')

   输入：娱乐新闻')delete category where id=3--

   等于：insert into category (name) values('娱乐新闻')delete category where id=3--')

 

⑥关于删除的时候删除其下的内容的触发器代码编写：

SET ANSI_NULLS ON
GO
 SET QUOTED_IDENTIFIER ON
GO
 -- =============================================
 -- Author:      haonanlyf
 -- Create date: 2012-7-8 10:37
 -- Description: 删除类别触发器
 -- =============================================
 CREATE TRIGGER trigCategoryDelete
    ON  Category
    AFTER DELETE
 AS
 BEGIN
     --把刚才删除的记录打印出来
     select * from deleted
 END
GO

 select top 10 n.id,n.title,n.createTime,c.[name] from news n
     inner join category c on n.caId=c.id
     order by n.createTime desc

 exec procNewsSeleteNewNews

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:		haonanlyf
-- Create date: 2012-7-8 10:37
-- Description:	删除类别触发器
-- =============================================
CREATE TRIGGER trigCategoryDelete
   ON  Category
   AFTER DELETE
AS 
BEGIN
	--把刚才删除的记录打印出来
	select * from deleted
END
GO

select top 10 n.id,n.title,n.createTime,c.[name] from news n
	inner join category c on n.caId=c.id
	order by n.createTime desc

exec procNewsSeleteNewNews

 

⑦

cmd.CommandType = CommandType.StoredProcedure;//将cmd类型改为存储过程

cmd.CommandType = CommandType.StoredProcedure;//将cmd类型改为存储过程

 

⑧记忆位置(视图、任务列表、注释)

   注释前面写成
   // TODO:XXX

 

⑨右键：插入代码段，选择#region，可以讲一个段包含起来，这样缩减到定义查看很清楚

 

10.删除按钮，客户端提示警告

OnClientClick="return confirm('删除新闻及其评论，确认删除么？')"

OnClientClick="return confirm('删除新闻及其评论，确认删除么？')"

 

 

11.报错弹窗

Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('新闻删除失败，请联系管理员！');</script>");

Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('新闻删除失败，请联系管理员！');</script>");

 

12.隐藏删除按钮

Visible="false"

 Visible="false"

 

13.【.cs】页面跳转

Response.Redirect("../newscontent.aspx?newsid=" + id);

Response.Redirect("../newscontent.aspx?newsid=" + id);

 

14.账号登陆Session

//登陆按钮
     protected void btnLogin_Click(object sender, EventArgs e)
    {
         //判断验证码是否输入正确
         string code = txtCode.Text.Trim().ToUpper();
         string rightCode = Session["Code"].ToString();
         //Response.Write("输入的验证码是：" + code + "，正确的验证码是：" + rightCode);
         if (code != rightCode)
        {
             Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('验证码输入错误！');</script>");
             return;
        }

         string name = txtName.Text.Trim();
         string pwd = txtPassword.Text.Trim();

         //把密码转为MD5码的形式
         pwd = FormsAuthentication.HashPasswordForStoringInConfigFile(pwd, "MD5");

         bool b = LoginManager.Login(name, pwd);
         if (b)
        {
             //管理员登陆会话从这里开始，知道浏览器关闭才结束
             Session["admin"] = name;
             //跳转语句
             Response.Redirect("categorymanager.aspx");
        }
         else
        {
             Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('登陆失败，用户名或者密码错误！');</script>");
        }


    }

//登陆按钮
    protected void btnLogin_Click(object sender, EventArgs e)
    {
        //判断验证码是否输入正确
        string code = txtCode.Text.Trim().ToUpper();
        string rightCode = Session["Code"].ToString();
        //Response.Write("输入的验证码是：" + code + "，正确的验证码是：" + rightCode);
        if (code != rightCode)
        {
            Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('验证码输入错误！');</script>");
            return;
        }

        string name = txtName.Text.Trim();
        string pwd = txtPassword.Text.Trim();

        //把密码转为MD5码的形式
        pwd = FormsAuthentication.HashPasswordForStoringInConfigFile(pwd, "MD5");

        bool b = LoginManager.Login(name, pwd);
        if (b)
        {
            //管理员登陆会话从这里开始，知道浏览器关闭才结束
            Session["admin"] = name;
            //跳转语句
            Response.Redirect("categorymanager.aspx");
        }
        else
        {
            Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('登陆失败，用户名或者密码错误！');</script>");
        }

        
    }

 

15.判断账号是否登陆

protected void Page_Load(object sender, EventArgs e)
    {
         //判断Session里面是否存在管理员
         if (Session["admin"] != null && Session["admin"].ToString() == "haonanlyf")
        {
             //若管理员已登陆
             if (!Page.IsPostBack)
            {
                 //绑定新闻分类到下拉列表
                 DataTable dt = new CategoryManager().SelectAll();
                ddlCategory.DataSource = dt;
                 ddlCategory.DataTextField = "name";
                 ddlCategory.DataValueField = "id";
                ddlCategory.DataBind();

                 //将需要修改的新闻标题内容显示出来
                 string id = Request.QueryString["id"];
                 News n = new NewsManager().SelectById(id);
                txtTitle.Text = n.Title;
                ftbContent.Text = n.Content;
                ddlCategory.SelectedValue = n.CaId;
            }
        }
         else
        {
             //未登陆返回登陆窗口
             Response.Redirect("login.aspx");
        }
    }