前一篇，已经把数据库个设计好了。剩下的就是照着文档进行编码了。
一.配置数据库连接
首先，第一步配置好数据库连接：
1.在app.config文件里添加连接字符串，如下代码：
1 <?xml version="1.0" encoding="utf-8" ?> 2 <configuration> 3 <configSections> 4 </configSections> 5 <connectionStrings> 6 <add name="sql_homework_end.Properties.Settings.sql_homework_endConnectionString" 7 connectionString="Data Source=.;Initial Catalog=sql_homework_end;Integrated Security=True" 8 providerName="System.Data.SqlClient" /> 9 </connectionStrings> 10 <startup> 11 <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> 12 </startup> 13 </configuration>
连接字符串
2.建立数据库公共类：
1 using System;
2 using System.Collections.Generic;
3 using System.Configuration;
4 using System.Data;
5 using System.Data.SqlClient;
6 using System.Linq;
7 using System.Security.Cryptography;
8 using System.Text;
9 using System.Threading.Tasks;
10
11 namespace sql_homework_end
12 {
13 class sqlhelper
14 {
15 private static string connStr = ConfigurationManager.ConnectionStrings["sql_homework_end.Properties.Settings.sql_homework_endConnectionString"].ConnectionString;
16 /// <summary>
17 /// 返回受影响的数据行数
18 /// </summary>
19 /// <param name="sql"></param>
20 /// <returns></returns>
21 public static int ExecuteNoQuery(string sql)
22 {
23 using (SqlConnection conn=new SqlConnection(connStr))
24 {
25 conn.Open();
26 using (SqlCommand cmd=conn.CreateCommand())
27 {
28 cmd.CommandText = sql;
29 return cmd.ExecuteNonQuery();
30
31 }
32 }
33 }
34 /// <summary>
35 /// 返回一个数据集
36 /// </summary>
37 /// <param name="sql"></param>
38 /// <returns></returns>
39 public static DataSet ExecuteDataSet(string sql)
40 {
41 using (SqlConnection xonn=new SqlConnection(connStr))
42 {
43 xonn.Open();
44 using (SqlCommand cmd = xonn.CreateCommand())
45 {
46 cmd.CommandText = sql;
47 SqlDataAdapter adapter = new SqlDataAdapter(cmd);
48 DataSet dataset = new DataSet();
49 adapter.Fill(dataset);
50 return dataset;
51 }
52 }
53 }
54 public static object ExecuteScalar(string sql)
55 {
56 using (SqlConnection conn=new SqlConnection(connStr))
57 {
58 conn.Open();
59 using (SqlCommand cmd=conn.CreateCommand())
60 {
61 cmd.CommandText = sql;
62 return cmd.ExecuteScalar();
63 }
64 }
65 }
66 /// <summary>
67 /// md5加密
68 /// </summary>
69 /// <param name="strPwd"></param>
70 /// <returns></returns>
71 public static string GetMD5(string strPwd)
72 {
73 string pwd = "";
74 //实例化一个md5对象
75 MD5 md5 = MD5.Create();
76 // 加密后是一个字节类型的数组
77 byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(strPwd));
78 //翻转生成的MD5码
79 s.Reverse();
80 //通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得
81 //只取MD5码的一部分，这样恶意访问者无法知道取的是哪几位
82 for (int i = 3; i < s.Length - 1; i++)
83 {
84 //将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符
85 //进一步对生成的MD5码做一些改造
86 pwd = pwd + (s[i] < 198 ? s[i] + 28 : s[i]).ToString("X");
87 }
88 return pwd;
89 }
90
91
92 }
93 }
二.功能设计
1.登录功能
界面预览：
功能应用有：身份验证，退出。公共变量传值。
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Threading.Tasks;
9 using System.Windows.Forms;
10
11 namespace sql_homework_end
12 {
13 public partial class login : Form
14 {
15 public login()
16 {
17 InitializeComponent();
18 }
19
20 //界面传值
21 public static string GlobelValue; // 注意，必须申明为static变量
22 //登录按钮事件
23 private void btn_login_Click(object sender, EventArgs e)
24 {
25 if (cmb_identity.Text.ToString()=="管理员")
26 {
27 verify_identidy("tb_admin","admin_name");
28 main a = new main();
29 a.Show();
30 }
31 else if (cmb_identity.Text.ToString()=="学生")
32 {
33 verify_identidy("tb_student","student_name");
34 studnet s = new studnet();
35 s.Show();
36 }
37
38 }
39 //身份验证的函数
40 private void verify_identidy(string table,string name)
41 {
42 DataSet ds = new DataSet();
43 ds = sqlhelper.ExecuteDataSet("select * from "+table+" where "+name+" = ‘" + tbx_loginname.Text + "‘");
44 DataTable dt = new DataTable();
45 dt = ds.Tables[0];
46 if (dt.Rows.Count != 0)
47 {
48 GlobelValue = tbx_loginname.Text;
49 this.Visible = false; //隐藏当前窗体
50 }
51 else
52 {
53 MessageBox.Show("用户名不存在，请重新输入");
54 }
55 }
56 //退出按钮
57 private void btn_close_Click(object sender, EventArgs e)
58 {
59 this.Close();
60 }
61
62
63
64 }
65 }
2.主界面-管理员
预览：
管理员信息：
学生信息：
主要使用控件：datagridview
相关代码：
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Threading.Tasks;
9 using System.Windows.Forms;
10
11 namespace sql_homework_end
12 {
13 public partial class main : Form
14 {
15 public main()
16 {
17 InitializeComponent();
18
19 }
20 //绑定并显示相关信息
21 DataSet ds = new DataSet();
22 DataTable dt = new DataTable();
23 private void 学生信息ToolStripMenuItem_Click(object sender, EventArgs e)
24 {
25 ds = sqlhelper.ExecuteDataSet("select * from tb_student");
26 dt = ds.Tables[0];
27 dataGridView1.DataSource = dt;
28 }
29
30 private void 课程信息ToolStripMenuItem_Click(object sender, EventArgs e)
31 {
32 ds = sqlhelper.ExecuteDataSet("select * from tb_course");
33 dt = ds.Tables[0];
34 dataGridView1.DataSource = dt;
35 }
36
37 private void 选课信息ToolStripMenuItem_Click(object sender, EventArgs e)
38 {
39 ds = sqlhelper.ExecuteDataSet("select * from tb_student_course");
40 dt = ds.Tables[0];
41 dataGridView1.DataSource = dt;
42 dataGridView1.Columns["sc_id"].DisplayIndex = 0;
43 }
44 private void 管理员信息ToolStripMenuItem_Click(object sender, EventArgs e)
45 {
46 ds = sqlhelper.ExecuteDataSet("select * from tb_admin");
47 dt = ds.Tables[0];
48 dataGridView1.DataSource = dt;
49 }
50 //添加按钮事件
51 private void btn_insert_Click(object sender, EventArgs e)
52 {
53 if (dataGridView1.Columns[0].HeaderText=="student_num")
54 {
55 string sql = @"insert tb_student (student_num,student_name,student_password,student_sex
56 ,student_age,student_dept)values(‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[0].Value + "‘,‘" +
57 dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[1].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[2].Value
58 + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[3].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[4].Value
59 + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[5].Value + "‘)";
60 sqlhelper.ExecuteNoQuery(sql);
61
62 }
63 else if (dataGridView1.Columns[0].HeaderText=="course_num")
64 {
65 string sql = @"insert tb_course (course_num,course_name,course_credit,course_semester)values(‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[0].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[1].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[2].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[3].Value + "‘)";
66 sqlhelper.ExecuteNoQuery(sql);
67 }
68 else if (dataGridView1.Columns[0].HeaderText=="sc_id")
69 {
70 try
71 {
72 string sql = @"insert tb_student_course (sc_id,student_num,course_num,grade)values(‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[0].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[1].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[2].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[3].Value + "‘)";
73 sqlhelper.ExecuteNoQuery(sql);
74 }
75 catch (Exception)
76 {
77 MessageBox.Show("学号或姓名不存在，请重新添加。");
78 }
79
80 }
81 else if (dataGridView1.Columns[0].HeaderText == "admin_id")
82 {
83 string sql = @"insert tb_admin (admin_id,admin_name,admin_password,remark)values(‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[0].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[1].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[2].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[3].Value + "‘)";
84 sqlhelper.ExecuteNoQuery(sql);
85 }
86 MessageBox.Show("添加成功");
87 }
88 //更新按钮事件
89 private void btn_update_Click(object sender, EventArgs e)
90 {
91 if (dataGridView1.Columns[0].HeaderText == "student_num")
92 {
93 update("tb_student","student_num");
94 }
95 else if (dataGridView1.Columns[0].HeaderText == "course_num")
96 {
97 update("tb_course","course_num");
98 }
99 else if (dataGridView1.Columns[0].HeaderText == "admin_id")
100 {
101 update("tb_admin","admin_id");
102 }
103 else if (dataGridView1.Columns[0].HeaderText == "sc_id")
104 {
105 try
106 {
107 update("tb_studnet_course","sc_id");
108 }
109 catch (Exception)
110 {
111 MessageBox.Show("学号或课程号不存在，请重新输入");
112 throw;
113 }
114 }
115 }
116 //更新方法
117 private void update(string table,string head_id)
118 {
119 for (int i = 0; i < dataGridView1.RowCount; i++)
120 {
121 int id = Convert.ToInt32(dataGridView1.Rows[i].Cells[0].Value);
122 for (int j = 1; j < dataGridView1.ColumnCount; j++)
123 {
124 if (dataGridView1.Columns[j].Visible == true)
125 {
126 string columnName = dataGridView1.Columns[j].Name.ToString();
127 string sql = "update " + table + " set " + columnName + "=‘" + dataGridView1.Rows[i].Cells[j].Value + "‘ where " + head_id + "=‘" + id + "‘";
128 sqlhelper.ExecuteNoQuery(sql);
129 }
130 }
131 }
132 MessageBox.Show("更新成功");
133 }
134
135 //删除事件
136 private void btn_delete_Click(object sender, EventArgs e)
137 {
138 if (dataGridView1.Columns[0].HeaderText == "student_num")
139 {
140 string sql = "delete from tb_student where student_num=‘" + dataGridView1.SelectedCells[0].Value + "‘";
141 sqlhelper.ExecuteNoQuery(sql);
142 }
143 else if (dataGridView1.Columns[0].HeaderText == "course_num")
144 {
145 string sql = "delete from tb_course where course_num=‘" + dataGridView1.SelectedCells[0].Value + "‘";
146 sqlhelper.ExecuteNoQuery(sql);
147 }
148 else if (dataGridView1.Columns[0].HeaderText == "sc_id")
149 {
150 string sql = "delete from tb_student_course where sc_id=‘" + dataGridView1.SelectedCells[0].Value + "‘";
151 sqlhelper.ExecuteNoQuery(sql);
152 }
153 else if (dataGridView1.Columns[0].HeaderText == "admin_id")
154 {
155 string sql = "delete from tb_admin where admin_id=‘" + dataGridView1.SelectedCells[0].Value + "‘";
156 sqlhelper.ExecuteNoQuery(sql);
157 }
158 MessageBox.Show("删除成功");
159 }
160
161 //界面载入显示身份和登录时间
162 private void main_Load(object sender, EventArgs e)
163 {
164 lbl_username.Text = "Welcome," + login.GlobelValue + "";
165 lbl_logintime.Text ="登录时间:" +DateTime.Now.ToString()+"";
166 }
167 }
168 }
3.学生界面
界面预览：
个人信息显示：在这个界面，学生能看到自己的信息，并进行修改操作。
代码：
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Threading.Tasks;
9 using System.Windows.Forms;
10
11 namespace sql_homework_end
12 {
13 public partial class studnet : Form
14 {
15 public studnet()
16 {
17 InitializeComponent();
18 }
19
20 DataSet ds = new DataSet();
21 DataTable dt = new DataTable();
22 private void studnet_Load(object sender, EventArgs e)
23 {
24 lbl_username.Text = "Welcome," + login.GlobelValue + "";
25 lbl_logintime.Text = "登录时间:" + DateTime.Now.ToString() + "";
26
27
28 }
29 //相关信息显示
30 private void 个人信息ToolStripMenuItem_Click(object sender, EventArgs e)
31 {
32 ds = sqlhelper.ExecuteDataSet("select * from tb_student where student_name=‘" + login.GlobelValue + "‘");
33 dt = ds.Tables[0];
34 dataGridView1.DataSource = dt;
35 btn_update.Visible = true;
36 btn_insert.Visible = false;
37 btn_delete.Visible = false;
38 }
39
40 private void 课程信息ToolStripMenuItem_Click(object sender, EventArgs e)
41 {
42
43 ds = sqlhelper.ExecuteDataSet("select * from tb_course");
44 dt = ds.Tables[0];
45 dataGridView1.DataSource = dt;
46 btn_update.Visible = false;
47 btn_insert.Visible = false;
48 btn_delete.Visible = false;
49 }
50
51 private void 选课管理ToolStripMenuItem_Click(object sender, EventArgs e)
52 {
53
54 ds = sqlhelper.ExecuteDataSet(@"select sc.sc_id,s.student_num,c.course_num,c.course_name,grade
55 from tb_student_course sc join tb_student s on sc.student_num=s.student_num
56 join tb_course c on sc.course_num=c.course_num
57 where s.student_name = ‘" + login.GlobelValue + "‘");
58 dt = ds.Tables[0];
59 dataGridView1.DataSource = dt;
60 dataGridView1.Columns["sc_id"].DisplayIndex = 0;
61 btn_update.Visible = false;
62 btn_insert.Visible = true;
63 btn_delete.Visible = true;
64 }
65 //学生选课功能
66 private void btn_insert_Click_1(object sender, EventArgs e)
67 {
68 if (Convert.ToInt32(dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[4].Value) > 0)
69 {
70 MessageBox.Show("不准填写成绩");
71 }
72 else
73 {
74 string sql = @"insert tb_student_course (sc_id,student_num,course_num)values(‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[0].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[1].Value + "‘,‘" + dataGridView1.Rows[dataGridView1.RowCount - 2].Cells[2].Value + "‘)";
75 sqlhelper.ExecuteNoQuery(sql);
76 MessageBox.Show("选课成功");
77 }
78 }
79 //删除选的课程
80 private void btn_delete_Click(object sender, EventArgs e)
81 {
82 string sql = "delete from tb_student_course where sc_id=‘" + dataGridView1.SelectedCells[0].Value + "‘";
83 sqlhelper.ExecuteNoQuery(sql);
84 MessageBox.Show("删除成功，请重新选课。");
85 }
86 //更新个人信息
87 private void btn_update_Click(object sender, EventArgs e)
88 {
89 update("tb_student", "student_num");
90 }
91 private void update(string table, string head_id)
92 {
93 for (int i = 0; i < dataGridView1.RowCount; i++)
94 {
95 int id = Convert.ToInt32(dataGridView1.Rows[i].Cells[0].Value);
96 for (int j = 1; j < dataGridView1.ColumnCount; j++)
97 {
98 if (dataGridView1.Columns[j].Visible == true)
99 {
100 string columnName = dataGridView1.Columns[j].Name.ToString();
101 string sql = "update " + table + " set " + columnName + "=‘" + dataGridView1.Rows[i].Cells[j].Value + "‘ where " + head_id + "=‘" + id + "‘";
102 sqlhelper.ExecuteNoQuery(sql);
103 }
104 }
105 }
106 MessageBox.Show("更新成功");
107 }
108
109 }
110 }
最后，写得有点乱啊。看不懂的话，可以看源码。
时间： 2024-10-12 15:42:06