deletetudent.cs

这是一个图书馆管理用的简化系统

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

namespace BMS
{
    public partial class deletetudent : Form
    {
        public deletetudent()
        {
            InitializeComponent();
        }
        public void data()
        {
            string selec = "select * from Reader";
            if (Operator.Datafill(selec).Rows.Count>0)
            dataGridView1.DataSource = Operator.Datafill(selec);
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            data();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //定义查询相关卡号学生信息的语句，　
            string s = "select * from Reader where readerid='" +textBox1.Text+ "'";
            //返回行数大于０则有信息
            if (Operator.Datafill(s).Rows.Count > 0)
                dataGridView1.DataSource = Operator.Datafill(s);
            else
            {
                MessageBox.Show("没有此卡号的学生信息");
                textBox1.Text = "";
                textBox1.Focus();
            }

        }

        private void button2_Click(object sender, EventArgs e)
        {
            //定义删除相关卡号学生信息的语句，
            string s = "select * from Reader where readerid='" + textBox1.Text + "'";
            if (Operator.Datafill(s).Rows.Count == 0)
                MessageBox.Show("没有此卡号的学生");
            string delete = "delete from Reader where readerid='" + textBox1.Text + "'";
            string seleReturn = "select * from BRinf where readerid='" + textBox1.Text + "'and IsReturn='否'";
            if (Operator.Datafill(seleReturn).Rows.Count > 0)
            {
                MessageBox.Show("此读者还有未还的图书");
            }
            else
            {
                if (Operator.ExecuteSql(delete) > 0)
                {
                    MessageBox.Show("删除成功");
                    textBox1.Text = "";
                    data();
                }
                else
                    MessageBox.Show("删除不成功");
            }
        }

        private void dataGridView1_MouseClick(object sender, MouseEventArgs e)
        {
            textBox1.Text = dataGridView1.CurrentRow.Cells[0].Value.ToString();
        }
    }
}