formstudentdelete.cs

学生管理系统Csharp2005 学生管理系统Csharp2005 学生管理系统Csharp2005

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

using StudentManager.DbLayer;

namespace StudentManager
{
    public partial class FormStudentDelete : Form
    {
        public FormStudentDelete()
        {
            InitializeComponent();
        }

        private void splitContainer1_Panel1_Paint(object sender, PaintEventArgs e)
        {

        }

        /// <summary>
        /// 初始化窗体中控件的数据
        /// </summary>
        void InitData()
        {
            //1 查询数据表Department中的院系数据，并绑定到“院系”下拉框中
            //构造查询SQL
            string sql = "";
            sql += "select * from [Department]";
            //查询
            Database db = new Database();
            SqlDataReader dr = db.GetDataReader(sql);
            //绑定到下拉框中
            comboBoxDepartment.Items.Clear();
            while (dr.Read())
            {
                comboBoxDepartment.Items.Add(GetSafeData.ValidateDataReader_S(dr, "DepartmentName"));
            }
        }

        /// <summary>
        /// 根据用户输入的院系、入学年份信息，查询学生的详细信息，并显示在DataGridView中
        /// </summary>
        void LoadDeleteStudents()
        {
            if (comboBoxDepartment.SelectedItem == null || comboBoxEnterYear.SelectedItem == null)
                return;

            //构造查询SQL
            string sql = "";
            sql += "select SNo,SName,SAge,SGender,DepartmentName,SEnterYear ";
            sql += " from [Student],[Department] where [Department].DepartmentName = ";
            sql += SqlStringConstructor.GetQuotedString(comboBoxDepartment.SelectedItem.ToString());
            sql += " and [Student].SEnterYear = ";
            sql += SqlStringConstructor.GetQuotedString(comboBoxEnterYear.SelectedItem.ToString());
            sql += " and [Student].SDepartmentId = [Department].DepartmentId";

            //查询
            Database db = new Database();
            DataTable dt = db.GetDataTable(sql);

            if (dt.Rows.Count == 0)
            {
                MessageBox.Show("数据库中没有满足条件的数据");
                this.dataGridViewPreView.DataSource = null;
                return;
            }

            //绑定到DataGriw
            this.dataGridViewPreView.DataSource = dt;
        }

        /// <summary>
        /// 窗体加载事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void FormStudentDelete_Load(object sender, EventArgs e)
        {
            this.InitData();
        }

        /// <summary>
        /// “修改”按钮单击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonDelete_Click(object sender, EventArgs e)
        {
            string sql = "";
            Database db = new Database();
            int departmentId = 0;

            //从Department表中，检索DepartmentId
            sql = "select DepartmentId from [Department] where DepartmentName = ";
            sql += SqlStringConstructor.GetQuotedString(comboBoxDepartment.SelectedItem.ToString());
            DataRow row = db.GetDataRow(sql);
            departmentId = GetSafeData.ValidateDataRow_N(row, "DepartmentId");

            //构造Delete语句        
            sql = "";
            sql += "Delete [student] ";
            sql += " Where SEnterYear = " + SqlStringConstructor.GetQuotedString(comboBoxEnterYear.SelectedItem.ToString());
            sql += " And SDepartmentId= " + departmentId;

            db.ExecuteSQL(sql);

            this.dataGridViewPreView.DataSource = null;
            MessageBox.Show("删除成功！");
        }

        /// <summary>
        /// “关闭”按钮单击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        /// <summary>
        /// 选择“入学年份”下拉框时，自动加载所有满足条件的学生数据
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void comboBoxEnterYear_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.LoadDeleteStudents();
        }

        /// <summary>
        /// 选择“院系”下拉框时，自动加载所有满足条件的学生数据
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void comboBoxDepartment_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.LoadDeleteStudents();
        }
    }
}