student_course.aspx.cs

C# SQL遍写的学生选课系统 给大家看看 有点多 有点复杂

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Configuration;

namespace sms
{
	/// <summary>
	/// student_course 的摘要说明。
	/// </summary>
	public partial class student_course : System.Web.UI.Page
	{
        private DataAccess DataAs;
		protected void Page_Load(object sender, System.EventArgs e)
		{   
            //教师名称下拉列表框绑定
			if(!IsPostBack)
			{
				string mysql="select * from teacher";
                DataAs = new DataAccess();
                DataTable DT = DataAs.CreateDatatable(mysql);
                for (int i = 0; i < DT.Rows.Count; i++)
                {
                    Ddl_teacher.Items.Add(new ListItem(DT.Rows[i][1].ToString(), DT.Rows[i][0].ToString()));
                }
				//课程名称下拉列表框绑定
				string mysql1="select * from course";
                DataTable DT2 = DataAs.CreateDatatable(mysql1);
                for (int i = 0; i < DT2.Rows.Count; i++)
                {
                    Ddl_course.Items.Add(new ListItem(DT2.Rows[i][1].ToString(), DT2.Rows[i][0].ToString()));
                }    
			}
			
		}

		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN：该调用是 ASP.NET Web 窗体设计器所必需的。
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{    

		}
		#endregion

		protected void Btn_student_Click(object sender, System.EventArgs e)
		{ 
            Bindgrid();		  
		}
		
		public void Bindgrid()
		{
			string strsql="select student_course.ID,student.Student_id,student.Student_classid from student_course,student,teacher_course where student_course.Course_id='"+
                        Ddl_course.SelectedItem.Value+"' and student_course.Course_year=teacher_course.Coure_year and student_course.Course_year='"+Tbx_year.Text+
                        "'and teacher_course.Teacher_id='"+Ddl_teacher.SelectedItem.Value+"'and student_course.Course_id=teacher_course.Course_id and student.Student_id=student_course.Student_id";
            DataAs = new DataAccess();
            DataTable DT = DataAs.CreateDatatable(strsql);
            GridView1.DataSource = DT;
            GridView1.DataBind();
			string strsql1="select COUNT(*) from student_course,student,teacher_course where student_course.Course_id='"+Ddl_course.SelectedItem.Value+"' and student_course.Course_year=teacher_course.Coure_year and student_course.Course_year='"+Tbx_year.Text+"'and teacher_course.Teacher_id='"+Ddl_teacher.SelectedItem.Value+"'and student_course.Course_id=teacher_course.Course_id and student.Student_id=student_course.Student_id";
            DataTable DT2 = DataAs.CreateDatatable(strsql1);
			if((int)DT2.Rows[0][0] >0)
			{
				Lbl_all.Text="选课总人数为："+DT.Rows[0][0].ToString();
			}
			else
			{
				Lbl_all.Text="无人选此课";
			}
			
		}

		protected void Btn_exit_Click(object sender, System.EventArgs e)
		{
			Response.Redirect("default.aspx");
		}

        protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
            string strsql = "delete from student_course where ID='" + GridView1.DataKeys[e.RowIndex].Value.ToString() + "'";
            DataAs = new DataAccess();
            bool Result = DataAs.ExecSql(strsql);
            if (Result)
            {
                Lbl_note.Text = "删除成功";

            }
            else
            {
                Lbl_note.Text = "删除失败";
                Lbl_note.Style["color"] = "red";
            }
            Bindgrid();

        }
        protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            GridView1.PageIndex = e.NewPageIndex;
            Bindgrid();
        }
}
}