C# 学习系统源码例子(access数据库)

【实例简介】

打开软件路径：MyLearningSystemQuery\MyLearningSystemQuery\bin\Debug\MyLearningSystemQuery.exe
数据库路径：MyLearningSystemQuery\MyLearningSystemQuery\MyLearginSystem.mdb
登录账号：admin 
登录密码：yun

登录账号2：1
登录密码2：1
如有出现登录不了，安装AccessDatabaseEngine.exe

如果发现 退出不了，打开任务管理器 结束

【核心代码】

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace MyLearningSystemQuery
{
    public partial class SystemInfo : Form
    {
        List<SystemInfos> list = new List<SystemInfos>();
        List<NameInfo> nlist = new List<NameInfo>();
        NameInfo n = null;
        SystemInfos s = null;
        OleDbConnection conn = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=..\\..\\MyLearginSystem.mdb");
        /// <summary>
        /// 初始化
        /// </summary>
        public SystemInfo()
        {
            InitializeComponent();

            Opacity = 0.9;//设置背景

            string sql = "select * from SystemInfo order by NaneID";
            using (OleDbCommand com = new OleDbCommand(sql, conn))
            {
                conn.Open();
                OleDbDataReader sr = com.ExecuteReader();
                while (sr.Read())
                {
                    s = new SystemInfos();
                    s.id = Convert.ToInt32(sr["ID"]);
                    s.NaneID = Convert.ToInt32(sr["NaneID"]);
                    s.SystemName = sr["SystemName"].ToString();
                    //s.MyName= sr["MyName"].ToString();
                    //s.MyUrl = sr["MyUrl"].ToString();
                    list.Add(s);
                }

            }
            foreach (var item in list)
            {
                string sqls = "select* from (select * from NameInfo where NameID = "   item.NaneID   ") order by ID";

                using (OleDbCommand comm = new OleDbCommand(sqls, conn))
                {

                    OleDbDataReader srr = comm.ExecuteReader();
                    while (srr.Read())
                    {
                        n = new NameInfo();
                        n.id = Convert.ToInt32(srr["ID"]);
                        n.NaneID = Convert.ToInt32(srr["NameID"]);

                        n.MyName = srr["MyName"].ToString();
                        n.MyUrl = srr["MyUrl"].ToString();
                        nlist.Add(n);
                    }

                }
                treeView1.Nodes.Add(item.SystemName);
                foreach (var item2 in nlist)
                {
                    foreach (TreeNode node in treeView1.Nodes)
                    {
                        if (node.Text == item.SystemName && item.NaneID == item2.NaneID)
                        {
                            int a = 0;
                            a = treeView1.Nodes.IndexOf(node);

                            treeView1.Nodes[a].Nodes.Add(item2.MyName);
                            this.webBrowser1.Url = new Uri(item2.MyUrl);




                        }
                    }


                }

            }
            timer1.Enabled = true;


            Update u = null;
            string usql = "select * from [Update]   ";

            using (OleDbCommand comu = new OleDbCommand(usql, conn))
            {
                OleDbDataReader sru = comu.ExecuteReader();
                if (sru.Read())
                {
                    u = new Update();
                    u.ID = Convert.ToInt32(sru["ID"]);
                    u.SystemName = sru["SystemName"].ToString();
                    u.UpdateName = sru["UpdateName"].ToString();
                    u.url = sru["url"].ToString();
                }
            }
            if (u.UpdateName.Equals("有更新版本"))
            {
                MessageBox.Show("地址："   u.url, "有更新版本：", MessageBoxButtons.YesNo, MessageBoxIcon.Exclamation);

            }
            label1.Text = u.SystemName;
        }

        private void SystemInfo_Load(object sender, EventArgs e)
        {

        }

        private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            foreach (var item in nlist)
            {
                if (e.Node.Text != "")
                    if (e.Node.Text == item.MyName)
                    {
                        webBrowser1.Url = new Uri(item.MyUrl);
                    }
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {


            label1.Left -= 1;
            if (label1.Left <= label1.Width * -1)
            {
                label1.Left = this.Width;
            }

        }

        private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            ((WebBrowser)sender).Document.Window.Error  = new HtmlElementErrorEventHandler(Window_Error);
        }

        private void Window_Error(object sender, HtmlElementErrorEventArgs e)
        {

            e.Handled = true;
        }

        private void SuppressScriptErrorsOnly(WebBrowser browser)
        {
            // 确信 ScriptErrorsSuppressed 设为 false. 
            browser.ScriptErrorsSuppressed = false;

            // 处理 DocumentCompleted 事件以访问 Document 对象.    
            browser.DocumentCompleted  =
                new WebBrowserDocumentCompletedEventHandler(
                    webBrowser1_DocumentCompleted);


        }
    }
}