student.aspx.cs

这是一个课程设计

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;

public partial class Student : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

        //读取信息
        if (!IsPostBack)
        {

            studentInfo();
            BindData();
            DDLBindData();
        
        }

    }

    //函数BindData用于读取GridView数据
    private void BindData()
    {
        
        string strSql = "SELECT [scID],[scName],[scContent],[scNum],[scMax],[scTeacher] FROM [scInfo]";
        scGV.DataSource = DBHelper.sqlLoad(strSql);
        scGV.DataBind();

    }

    //函数DDLBindData用于读取选课下拉框的数据
    public void DDLBindData()
    {

        string strSql = "SELECT [scID],[scName] FROM [scInfo]";
        scDDL.DataSource = DBHelper.sqlLoad(strSql);
        scDDL.AppendDataBoundItems = true;
        scDDL.DataTextField = "scName";
        scDDL.DataValueField = "scID";
        scDDL.DataBind();
    
    }

    //函数studentInfo用于读取页面基本信息
    public void studentInfo()
    {

        //将Session实体化
        int userID = Int32.Parse(Session["uid"].ToString());

        //根据用户编号实例化用户信息
        string strSql = "SELECT [userID],[userLoginID],[userPwd],[userName],[userStauts],[scID] FROM [userInfo] WHERE [userID] ='" + userID + "'";
        UserInfo userinfo = new UserInfo();
        userinfo = DBHelper.sqllogin(strSql);

        //显示用户姓名
        txtName.Text = userinfo.UserName;

        //进行用户是否已经选课的判断
        if (userinfo.ScID == 0)
        {      

            //若尚未选课，则显示下拉框和选课按钮，并隐藏退选按钮
            txtContent.Text = "请选择课程";
            scDDL.Visible = true;
            Button1.Visible = true;
            Button2.Visible = false;

        }
        else
        {

            //若已有选课，则实例化课程信息，读取已选择的课程名称，显示退选按钮，并隐藏下拉框和选课按钮
            strSql = "SELECT [scID],[scName],[scContent],[scNum],[scMax],[scTeacher] FROM [scInfo] WHERE [scID] ='" + userinfo.ScID + "'";
            scInfo scinfo = new scInfo();
            scinfo = DBHelper.sqlsclogin(strSql);

            txtContent.Text = "您已经选择了<" + scinfo.ScName + ">作为您的选修课程！";
            scDDL.Visible = false;
            Button1.Visible = false;
            Button2.Visible = true;

        }

    }

    //退出
    protected void exitLB_Click(object sender, EventArgs e)
    {
        //清除Session储存内容，并跳转至登录界面
        Session.Clear();
        Response.Redirect("Login.aspx");

    }

    //选课
    protected void Button1_Click(object sender, EventArgs e)
    {

        //实例化下拉框所选定的课程信息
        string strSql = "SELECT [scID],[scName],[scContent],[scNum],[scMax],[scTeacher] FROM [scInfo] WHERE [scID] ='" + scDDL.SelectedValue + "'";
        scInfo scinfo = new scInfo();
        scinfo = DBHelper.sqlsclogin(strSql);

        //判断该课程是否满员
        if (scinfo.ScNum == scinfo.ScMax)
        {

            txtMsg.Text = "此课程已满员！";

        }
        else
        {

            //将Session实体化
            int userID = Int32.Parse(Session["uid"].ToString());

            //修改该用户的选课信息
            strSql = "UPDATE [userInfo] SET [scID]='" + scDDL.SelectedValue + "' WHERE [userID] ='" + userID + "'";
            int i = DBHelper.sqlinit(strSql);

            //增加该课程的已选人数
            strSql = "UPDATE [scInfo] SET [scNum]=[scNum]+1 WHERE [scID] ='" + scDDL.SelectedValue + "'";
            i = DBHelper.sqlinit(strSql);

            if (i > 0)
            {
                txtMsg.Text = "选课成功！";
            }

            //刷新GridView数据和页面基本信息
            studentInfo();
            BindData();

        }

    }

    //退选
    protected void Button2_Click(object sender, EventArgs e)
    {

        //将Session实体化
        int userID = Int32.Parse(Session["uid"].ToString());

        //根据用户编号实例化用户信息
        string strSql = "SELECT [userID],[userLoginID],[userPwd],[userName],[userStauts],[scID] FROM [userInfo] WHERE [userID] ='" + userID + "'";
        UserInfo userinfo = new UserInfo();
        userinfo = DBHelper.sqllogin(strSql);

        //修改该用户的选课信息
        strSql = "UPDATE [userInfo] SET [scID]=0 WHERE [userID] ='" + userID + "'";
        int i = DBHelper.sqlinit(strSql);

        //减少该课程的已选人数
        strSql = "UPDATE [scInfo] SET [scNum]=[scNum]-1 WHERE [scID] ='" + userinfo.ScID + "'";
        i = DBHelper.sqlinit(strSql);

        if (i > 0)
        {
            txtMsg.Text = "退选成功！";
        }

        //刷新GridView数据和页面基本信息
        studentInfo();
        BindData();

    }
}