C#实现图书管理系统（课程设计）——第五步、查询界面及操作

上一篇：借书界面

（1）界面设计：

前三个框为DataGridView控件，具体的使用方法自行百度，以下简单讲解：

1.创建后点击，右上角会有个小三角，点下它，会出现一个数据源的选择

2.在里面找到你需要的那一个表，是表，表，表，说三遍。不是数据库，具体到“表”，第四遍。

3.他就会直接显示出来表的所有数据

4.在框体load函数中会出现类似于this.studentTableAdapter.Fill(this.for_LoginDataSet.Student);

的代码，注释掉就，数据就不会打开窗体即展示

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下方选择书名、书本编号等控件是ComboBox，这个就比较简单了，自行百度

（2）界面源代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Util;
using System.Data.SqlClient;namespace LogIn
{public partial class search2 : Form{public search2(){InitializeComponent();}private void search2_Load(object sender, EventArgs e){// TODO: 这行代码将数据加载到表“for_LoginDataSet.Student”中。您可以根据需要移动或删除它。//this.studentTableAdapter.Fill(this.for_LoginDataSet.Student);// TODO: 这行代码将数据加载到表“for_LoginDataSet.rent”中。您可以根据需要移动或删除它。//this.rentTableAdapter.Fill(this.for_LoginDataSet.rent);// TODO: 这行代码将数据加载到表“for_LoginDataSet.books”中。您可以根据需要移动或删除它。//this.booksTableAdapter.Fill(this.for_LoginDataSet.books);}//三个按钮刷新三个框的内容private void button1_Click(object sender, EventArgs e){//数据库连接SqlConnection sqlCon;sqlCon = DbUtil.getConnection();sqlCon.Open();//数据库操作string sqlsearch = "select * from books";SqlCommand command = new SqlCommand(sqlsearch, sqlCon);SqlDataAdapter sda = new SqlDataAdapter(sqlsearch, sqlCon);DataSet tS = new DataSet();sda.Fill(tS);dataGridView1.DataSource = tS.Tables[0];//dataGridView2.DataSource = tS.Tables[2];//dataGridView3.DataSource = tS.Tables[1];}private void button2_Click(object sender, EventArgs e){//数据库连接SqlConnection sqlCon;sqlCon = DbUtil.getConnection();sqlCon.Open();//数据库操作string sqlsearch = "select * from rent";SqlCommand command = new SqlCommand(sqlsearch, sqlCon);SqlDataAdapter sda = new SqlDataAdapter(sqlsearch, sqlCon);DataSet tS = new DataSet();sda.Fill(tS);dataGridView2.DataSource = tS.Tables[0];}private void button3_Click(object sender, EventArgs e){//数据库连接SqlConnection sqlCon;sqlCon = DbUtil.getConnection();sqlCon.Open();//数据库操作string sqlsearch = "select * from Student";SqlCommand command = new SqlCommand(sqlsearch, sqlCon);SqlDataAdapter sda = new SqlDataAdapter(sqlsearch, sqlCon);DataSet tS = new DataSet();sda.Fill(tS);dataGridView3.DataSource = tS.Tables[0];}private void button4_Click(object sender, EventArgs e){DataSet empty = new DataSet();dataGridView1.DataSource = empty;dataGridView2.DataSource = empty;dataGridView3.DataSource = empty;bookname.Text = "选择书名";stname.Text = "选择姓名";}private void button5_Click(object sender, EventArgs e){string bkname = bookname.Text;string Stname = stname.Text;if (bkname == "选择书名" && Stname == "选择姓名"){ MessageBox.Show("请选择书名或姓名"); return; }try{//数据库连接SqlConnection sqlCon;sqlCon = DbUtil.getConnection();sqlCon.Open();//数据库操作string sqlsearch = "select * from books where 书名 = '" + bkname + "';select * from Student where 姓名 = '" + Stname + "'";SqlCommand command = new SqlCommand(sqlsearch, sqlCon);SqlDataAdapter sda = new SqlDataAdapter(sqlsearch, sqlCon);DataSet tS = new DataSet();sda.Fill(tS);dataGridView1.DataSource = tS.Tables[0];dataGridView3.DataSource = tS.Tables[1];}catch (Exception error){MessageBox.Show("查询不存在");}}private void button6_Click(object sender, EventArgs e){string bkid = Bkid.Text;string stid = Stid.Text;if (bkid == "" || stid == ""){ MessageBox.Show("请选择书编号和学号"); return; }try{//数据库连接SqlConnection sqlCon;sqlCon = DbUtil.getConnection();sqlCon.Open();//数据库操作string sqlsearch = "select 学号,编号 from rent where 编号 =  '" + bkid + "' and 学号 =  '" + stid + "';select * from books where 编号 = '" + bkid + "';select * from Student where 学号 = '" + stid + "'";SqlCommand command = new SqlCommand(sqlsearch, sqlCon);SqlDataAdapter sda = new SqlDataAdapter(sqlsearch, sqlCon);DataSet tS = new DataSet();sda.Fill(tS);dataGridView2.DataSource = tS.Tables[0];dataGridView1.DataSource = tS.Tables[1];dataGridView3.DataSource = tS.Tables[2];}catch (Exception error1){MessageBox.Show("错误");}}}
}

这里的数据库操作就没用另起一个csharp类，而是直接写在的按钮当中，最终效果一样，上一篇与第二篇的操作都是写在了另一个命名空间，用using来调用。