st_grade_query.aspx.cs

学生管理系统。C#开发。偏重与数据库的应用。

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;
using System.Data.SqlClient;
public partial class ST_grade_query : System.Web.UI.Page
{
    string st_sqlstr;
    protected System.Web.UI.WebControls.Button st_btn_look; SqlConnection st_conn;
    protected void Page_Load(object sender, EventArgs e)
    {
        // 在此处放置用户代码以初始化页面
        string st_connstr = ConfigurationManager.AppSettings["st_dbconn"];
        st_conn = new SqlConnection(st_connstr);
    }

    protected void st_btn_ok_Click(object sender, EventArgs e)
    {
        //当课程名称为空时，执行下面代码
        if (st_tbx_course.Text == "")
        {
            st_sqlstr = "select ST_course.ST_Course_name,ST_student_course.ST_Course_id,ST_Course_year,ST_Student_grade,ST_Course_credit,ST_Course_kind from ST_student_course,ST_course where ST_Course_year='" + st_tbx_term.Text + "' and ST_student_course.ST_Course_id=ST_course.ST_Course_id and ST_Student_id='" + Session["User_id"].ToString() + "'";

        }
        //当课程名称非空时，执行下面代码
        else
        {
            st_sqlstr = "select ST_course.ST_Course_name,ST_student_course.ST_Course_id,ST_Course_year,ST_Student_grade,ST_Course_credit,ST_Course_kind from ST_student_course,ST_course where ST_Course_year='" + st_tbx_term.Text + "'and ST_course.ST_Course_id=ST_student_course.ST_Course_id and ST_course.ST_Course_name='" + st_tbx_course.Text + "'and ST_Student_id='" + Session["User_id"].ToString() + "'";
        }
        st_conn.Open();
        SqlDataAdapter st_da = new SqlDataAdapter(st_sqlstr, st_conn);
        DataSet st_ds = new DataSet();
        st_da.Fill(st_ds);
        st_dtg_grade.DataSource = st_ds;
        st_dtg_grade.DataBind();
        st_conn.Close();
        //在Label中显示信息
        display();
    }
    //选出必修课总学分和选修课总学分显示在Label中
    public void display()
    {
        //选出非选修课总学分，条件是必须及格
        st_sqlstr = "select SUM(ST_Course_credit) from ST_course,ST_student_course where ST_Course_year='" + st_tbx_term.Text + "' and ST_Student_id=@Student_id and ST_student_course.ST_Course_id=ST_course.ST_Course_id and ST_Course_kind=2 and ST_Student_grade>=60";
        SqlCommand st_comm = new SqlCommand(st_sqlstr, st_conn);
        st_comm.Parameters.Add(new SqlParameter("@Student_id", SqlDbType.VarChar, 50));
        st_comm.Parameters["@Student_id"].Value = Session["User_id"].ToString();
        st_conn.Open();
        SqlDataReader dr = st_comm.ExecuteReader();
        if (dr.Read())
        {
            st_lbl_sort.Text = "本学期选修课的总学分为：" + dr[0].ToString();
        }
        else
        {
            st_lbl_sort.Text = "本学期选修课的总学分为：0";
        }
        st_conn.Close();
        //选出选修课总学分，条件是必须及格
        st_sqlstr = "select SUM(ST_Course_credit) from ST_course,ST_student_course where ST_Course_year='" + st_tbx_term.Text + "' and ST_Student_id=@Student_id and ST_student_course.ST_Course_id=ST_course.ST_Course_id and ST_Course_kind<2 and ST_Student_grade>=60";
        st_comm = new SqlCommand(st_sqlstr, st_conn);
        st_comm.Parameters.Add(new SqlParameter("@Student_id", SqlDbType.VarChar, 50));
        st_comm.Parameters["@Student_id"].Value = Session["User_id"].ToString();
        st_conn.Open();
        dr = st_comm.ExecuteReader();
        if (dr.Read())
        {
            st_lbl_must.Text = "本学期必修课的总学分为：" + dr[0].ToString();
        }
        else
        {
            st_lbl_must.Text = "本学期必修课的总学分为：0";
        }
        st_conn.Close();
    }
}