electtotallist.aspx.cs

基于asp.net的网上选课系统

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 ElectTotalList : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string str;
        
        if (!IsPostBack)
        {
            str = "select e.StudentID,s.StudentName,c.*,t.TeacherName";
            str = str + " from Elective e,Courses c,Students s,Teachers t";
            str = str + " where c.CourseID=e.CourseID and s.StudentID=e.StudentID";
            str = str + " and t.TeacherID=c.TeacherID order by 1,3";

            //设置分页控件的数据源
            Pg1.datalist1 = DataList1;
            Pg1.CmdStr = str;
            ViewState["str"] = Pg1.CmdStr;
        }
        Pg1.CmdStr = (string)ViewState["str"];
        Pg1.datalist1 = DataList1;
        //设置DataList控件的可见性
        DataList1.Visible = true;
        DataList2.Visible = false;
        DataList3.Visible = false;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
       string str;

       //根据Button的CommangName判断按下了哪个按钮
        switch (((Button)sender).CommandName)
        {
            case "a":
                if (drpident.SelectedValue == "student")
                {
                    str = "select e.StudentID,s.StudentName,c.*,t.TeacherName";
                    str = str + " from Elective e,Courses c,Students s,Teachers t";
                    str = str + " where c.CourseID=e.CourseID and s.StudentID=e.StudentID";
                    str = str + " and t.TeacherID=c.TeacherID and s.StudentID=" + "'" + txtid.Text.Trim() + "'";
                }
                else
                {
                    str = "select e.StudentID,s.StudentName,c.*,t.TeacherName";
                    str = str + " from Elective e,Courses c,Students s,Teachers t";
                    str = str + " where c.CourseID=e.CourseID and s.StudentID=e.StudentID";
                    str = str + " and t.TeacherID=c.TeacherID and t.TeacherID=" + "'" + txtid.Text.Trim() + "'";
                }
                //设置分页控件的数据源
                Pg1.CmdStr = str;
                Pg1.datalist1 = DataList1;
                ViewState["str"] = Pg1.CmdStr;
                Pg1.recordchanged();

                DataList1.Visible = true;
                DataList2.Visible = false;
                DataList3.Visible = false;

                txtid.Text = "";
                drpident.SelectedIndex = 0;

                break;
            case "b":
                str = "select StudentID,StudentName from Students where StudentID not in";
                str = str + "(select StudentID from Elective)";
                //设置分页控件的数据源
                Pg1.CmdStr = str;
                Pg1.datalist1 = DataList2;
                ViewState["str"] = Pg1.CmdStr;
                Pg1.recordchanged();

                DataList1.Visible = false;
                DataList2.Visible = true;
                DataList3.Visible = false;

                break;

            case "c":
                str = "select s.StudentID,s.StudentName from Students s inner join Elective e";
                str = str + " on s.StudentID=e.StudentID group by s.StudentID,s.StudentName";
                str=str+" having Count(*)<2 and Count(*)>=1";
                //设置分页控件的数据源
                Pg1.CmdStr = str;
                Pg1.datalist1 = DataList2;
                ViewState["str"] = Pg1.CmdStr;
                Pg1.recordchanged();

                DataList1.Visible = false;
                DataList2.Visible = true;
                DataList3.Visible = false;

                break;
            case "d":
                str="select c.*,t.TeacherName from Courses c inner join Teachers t on c.TeacherID=t.TeacherID";
                str = str + " where CourseID not in(select CourseID from Elective)";
                //设置分页控件的数据源
                Pg1.CmdStr = str;
                Pg1.datalist1 = DataList3;
                ViewState["str"] = Pg1.CmdStr;
                Pg1.recordchanged();

                DataList1.Visible = false;
                DataList2.Visible = false;
                DataList3.Visible = true;
                break;
            default:
                str = "select e.StudentID,s.StudentName,c.*,t.TeacherName";
                str = str + " from Elective e,Courses c,Students s,Teachers t";
                str = str + " where c.CourseID=e.CourseID and s.StudentID=e.StudentID";
                str = str + " and t.TeacherID=c.TeacherID order by 1,3";
                //设置分页控件的数据源
                Pg1.CmdStr = str;
                Pg1.datalist1 = DataList1;
                ViewState["str"] = Pg1.CmdStr;
                Pg1.recordchanged();

                DataList1.Visible = true;
                DataList2.Visible = false;
                DataList3.Visible = false;
                break;
        }
    }

}