Winform的三层架构详细案例分析 写了几个Winform程序后发现一个类的行数直逼2000行...维护十分困难,想起来之前学过三层架构,转篇文章记录一下！三层架构将整个业务应用划分为：（1）界面UI层；（2）业务逻辑层；（3）数据访问层。对于复杂的系统分层可以让结构更加清晰，模块更加独立，便于维护。各层的任务：（1）数据访问层：负责数据库的操作。（2）业务逻辑层：实现功能模块的业务逻辑。（3）界面UI层：绘制界面，以及负责界面相关代码。（4）实体类：将数据库中的表转化为面向对象思想中的类。一、案例需求使用三层架构实现学生管理：（1）专业下拉框绑定专业表数据，网格控件绑定学生数据，并且点击"搜索"按钮可以多条件组合查询。（2）选中某一行，右键可以弹出"删除"菜单，点击"删除"菜单可以删除学生数据。（3）点击"新增"按钮，弹出新增窗体，在此窗体中完成学生的新增操作。（4）选中某一行，点击"编辑"按钮，弹出编辑窗体，在此窗体中完成数据的修改。备注：其中性别的单选框，以及爱好的多选框分别用两个Pannel容器包含。数据库准备：--专业 create table ProfessionInfo ( ProfessionID int primary key identity(1,1), --专业编号 ProfessionName varchar(50) not null unique --专业名称 ) --学生 create table StudentInfo ( StuID varchar(20) primary key, --学生学号 StuName varchar(50) not null, --学生姓名 StuAge int not null check(StuAge > 0 and StuAge < 130), --学生年龄 StuSex char(2) not null check(StuSex in('男','女')), --学生性别 StuHobby nvarchar(100), --爱好 ProfessionID int not null references ProfessionInfo(ProfessionID), --所属专业编号 ) --添加专业信息 insert into ProfessionInfo(ProfessionName) values('电子竞技') insert into ProfessionInfo(ProfessionName) values('软件开发') insert into ProfessionInfo(ProfessionName) values('医疗护理') --插入学生信息 insert into StudentInfo(StuID,StuName,StuAge,StuSex,StuHobby,ProfessionID) values('001','刘备',18,'男','',1) insert into StudentInfo(StuID,StuName,StuAge,StuSex,StuHobby,ProfessionID) values('002','关羽',20,'男','',2) insert into StudentInfo(StuID,StuName,StuAge,StuSex,StuHobby,ProfessionID) values('003','张飞',19,'男','',2) insert into StudentInfo(StuID,StuName,StuAge,StuSex,StuHobby,ProfessionID) values('004','孙尚香',17,'女','',3)二、项目结构（1）创建一个空白解决方案。（2）在解决方案中创建类库项目MyEntity代表"实体类"。（3）在解决方案中创建类库项目MyDAL代表"数据访问层"。（4）在解决方案中创建类库项目MyBLL代表"业务逻辑层"。（5）在解决方案中创建Windows窗体应用程序MyUI代表"界面UI层"。三、实体类编写在MyEntity项目中添加两个实体类，实体类代码如下：ProfessionInfoEntity： public class ProfessionInfoEntity { public ProfessionInfoEntity() { this.ProfessionID = 0; this.ProfessionName = ""; } public int ProfessionID { get; set; } //专业编号 public string ProfessionName { get; set; }//专业名称 }StudentInfoEntiy：public class StudentInfoEntiy { public StudentInfoEntiy() { this.StuID = ""; this.StuName = ""; this.StuAge = 0; this.StuSex = ""; this.StuHobby = ""; this.ProfessionID = 0; this.ProfessionName = ""; } public string StuID { get; set; } //学生学号 public string StuName { get; set; } //学生姓名 public int StuAge { get; set; } //学生年龄 public string StuSex { get; set; } //学生性别 public string StuHobby { get; set; } //学生爱好 public int ProfessionID { get; set; } //学生所属专业编号 public string ProfessionName { get; set; } //学生所属专业名称 }四、数据访问层编写（1）由于数据访问层需要使用实体类，所以需要添加实体类的引用。即在MyDAL项目上右键-->添加-->引用-->项目，在项目中勾选MyEntity项目。（2）将之前封装好的DBHelper文件复制到MyDAL项目中，并通过添加现有项，将DBHelper加入项目。（3）在MyDAL项目中添加两个类，类代码如下：ProfessionInfoDAL：public class ProfessionInfoDAL { #region 新增 public int Add(ProfessionInfoEntity entity) { string sql = "insert into ProfessionInfo(professionName) values(@professionName)"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("ProfessionName",entity.ProfessionName); return DBHelper.ExecNonQuery(); } #endregion #region 删除 public int Delete(int id) { string sql = "delete from ProfessionInfo where ProfessionID=@ProfessionID"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("ProfessionID", id); return DBHelper.ExecNonQuery(); } #endregion #region 修改 public int Update(ProfessionInfoEntity entity) { string sql = "update ProfessionInfo set professionName=@professionName where ProfessionID=@ProfessionID"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("professionName", entity.ProfessionName); DBHelper.SetParameter("ProfessionID", entity.ProfessionID); return DBHelper.ExecNonQuery(); } #endregion #region 列表 public List<ProfessionInfoEntity> List() { string sql = "select * from ProfessionInfo"; DataTable dt = new DataTable(); DBHelper.PrepareSql(sql); dt = DBHelper.ExecQuery(); List<ProfessionInfoEntity> list = new List<ProfessionInfoEntity>(); foreach (DataRow item in dt.Rows) { ProfessionInfoEntity entity = new ProfessionInfoEntity(); entity.ProfessionID = int.Parse(item["ProfessionID"].ToString()); entity.ProfessionName = item["ProfessionName"].ToString(); list.Add(entity); } return list; } #endregion #region 详情 public ProfessionInfoEntity Detail(int id) { string sql = "select * from ProfessionInfo where ProfessionID=@ProfessionID"; DataTable dt = new DataTable(); DBHelper.PrepareSql(sql); DBHelper.SetParameter("ProfessionID", id); dt = DBHelper.ExecQuery(); if (dt.Rows.Count == 0) return null; ProfessionInfoEntity entity = new ProfessionInfoEntity(); entity.ProfessionID = int.Parse(dt.Rows[0]["ProfessionID"].ToString()); entity.ProfessionName = dt.Rows[0]["ProfessionName"].ToString(); return entity; } #endregion }StudentInfoDAL：public class StudentInfoDAL { #region 新增 public int Add(StudentInfoEntiy entity) { string sql = "insert into StudentInfo(StuID,StuName,StuAge,StuSex,StuHobby,ProfessionID) values(@StuID,@StuName,@StuAge,@StuSex,@StuHobby,@ProfessionID)"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("StuID", entity.StuID); DBHelper.SetParameter("StuName", entity.StuName); DBHelper.SetParameter("StuAge", entity.StuAge); DBHelper.SetParameter("StuSex", entity.StuSex); DBHelper.SetParameter("StuHobby", entity.StuHobby); DBHelper.SetParameter("ProfessionID", entity.ProfessionID); return DBHelper.ExecNonQuery(); } #endregion #region 删除 public int Delete(string id) { string sql = "delete from StudentInfo where StuID=@StuID"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("StuID", id); return DBHelper.ExecNonQuery(); } #endregion #region 修改 public int Update(StudentInfoEntiy entity) { string sql = "update StudentInfo set StuName=@StuName,StuAge=@StuAge,StuSex=@StuSex,StuHobby=@StuHobby,ProfessionID=@ProfessionID where StuID=@StuID"; DBHelper.PrepareSql(sql); DBHelper.SetParameter("StuName", entity.StuName); DBHelper.SetParameter("StuAge", entity.StuAge); DBHelper.SetParameter("StuSex", entity.StuSex); DBHelper.SetParameter("StuHobby", entity.StuHobby); DBHelper.SetParameter("ProfessionID", entity.ProfessionID); DBHelper.SetParameter("StuID", entity.StuID); return DBHelper.ExecNonQuery(); } #endregion #region 列表 public List<StudentInfoEntiy> List() { string sql = "select * from StudentInfo"; DataTable dt = new DataTable(); DBHelper.PrepareSql(sql); dt = DBHelper.ExecQuery(); List<StudentInfoEntiy> list = new List<StudentInfoEntiy>(); foreach (DataRow item in dt.Rows) { StudentInfoEntiy entity = new StudentInfoEntiy(); entity.StuID = item["StuID"].ToString(); entity.StuName = item["StuName"].ToString(); entity.StuAge = int.Parse(item["StuAge"].ToString()); entity.StuSex = item["StuSex"].ToString(); entity.StuHobby = item["StuHobby"].ToString(); entity.ProfessionID = int.Parse(item["ProfessionID"].ToString()); list.Add(entity); } return list; } #endregion #region 详情 public StudentInfoEntiy Detail(string id) { string sql = "select * from StudentInfo where StuID=@StuID"; DataTable dt = new DataTable(); DBHelper.PrepareSql(sql); DBHelper.SetParameter("StuID", id); dt = DBHelper.ExecQuery(); if (dt.Rows.Count == 0) return null; StudentInfoEntiy entity = new StudentInfoEntiy(); entity.StuID = dt.Rows[0]["StuID"].ToString(); entity.StuName = dt.Rows[0]["StuName"].ToString(); entity.StuAge = int.Parse(dt.Rows[0]["StuAge"].ToString()); entity.StuSex = dt.Rows[0]["StuSex"].ToString(); entity.StuHobby = dt.Rows[0]["StuHobby"].ToString(); entity.ProfessionID = int.Parse(dt.Rows[0]["ProfessionID"].ToString()); return entity; } #endregion }五、业务逻辑层编写（1）由于业务逻辑层需要使用实体类，所以需要添加实体类的引用。即在MyBLL项目上右键-->添加-->引用-->项目，在项目中勾选MyEntity项目。（2）由于业务逻辑层需要调用数据访问层，所以需要添加数据访问层的引用。即在MyBLL项目上右键-->添加-->引用-->项目，在项目中勾选MyDAL项目。（3）在MyBLL项目中添加两个类，类代码如下：ProfessionInfoBLL：public class ProfessionInfoBLL { ProfessionInfoDAL dal = new ProfessionInfoDAL(); #region 新增 public int Add(ProfessionInfoEntity entity) { return dal.Add(entity); } #endregion #region 删除 public int Delete(int id) { return dal.Delete(id); } #endregion #region 修改 public int Update(ProfessionInfoEntity entity) { return dal.Update(entity); } #endregion #region 列表 public List<ProfessionInfoEntity> List() { return dal.List(); } #endregion #region 详情 public ProfessionInfoEntity Detail(int id) { return dal.Detail(id); } #endregion }StudentInfoBLL：public class StudentInfoBLL { StudentInfoDAL dal = new StudentInfoDAL(); #region 新增 public int Add(StudentInfoEntiy entity) { return dal.Add(entity); } #endregion #region 删除 public int Delete(string id) { return dal.Delete(id); } #endregion #region 修改 public int Update(StudentInfoEntiy entity) { return dal.Update(entity); } #endregion #region 列表 public List<StudentInfoEntiy> List() { return dal.List(); } #endregion #region 详情 public StudentInfoEntiy Detail(string id) { return dal.Detail(id); } #endregion }六、界面UI层代码编写（1）由于界面UI层需要使用实体类，所以需要添加实体类的引用。即在MyUI项目上右键-->添加-->引用-->项目，在项目中勾选MyEntity项目。（2）由于界面UI层需要调用业务逻辑层，所以需要添加业务逻辑层的引用。即在MyUI项目上右键-->添加-->引用-->项目，在项目中勾选MyBLL项目。查询窗体界面及代码：（1）由于查询学生需要多条件组合查询，所以给数据访问层和业务逻辑层添加条件搜索的方法。给数据访问层MyDAL中StudentInfoDAL类添加方法：#region 条件查询 public List<StudentInfoEntiy> Search(StudentInfoEntiy searchObj) { string sql = "select * from StudentInfo inner join ProfessionInfo on StudentInfo.ProfessionID = ProfessionInfo.ProfessionID where 1 = 1"; if (searchObj.ProfessionID != 0) sql += " and StudentInfo.ProfessionID = " + searchObj.ProfessionID; if (!searchObj.StuName.Equals("")) sql += " and StuName like '%" + searchObj.StuName + "%'"; DataTable dt = new DataTable(); DBHelper.PrepareSql(sql); dt = DBHelper.ExecQuery(); List<StudentInfoEntiy> list = new List<StudentInfoEntiy>(); foreach (DataRow item in dt.Rows) { StudentInfoEntiy entity = new StudentInfoEntiy(); entity.StuID = item["StuID"].ToString(); entity.StuName = item["StuName"].ToString(); entity.StuAge = int.Parse(item["StuAge"].ToString()); entity.StuSex = item["StuSex"].ToString(); entity.StuHobby = item["StuHobby"].ToString(); entity.ProfessionID = int.Parse(item["ProfessionID"].ToString()); entity.ProfessionName = item["ProfessionName"].ToString(); list.Add(entity); } return list; } #endregion给业务逻辑层MyBLL中StudentInfoBLL类添加方法：#region 条件查询 public List<StudentInfoEntiy> Search(StudentInfoEntiy searchObj) { return dal.Search(searchObj); } #endregion（2）在此界面中多个功能需要调用业务逻辑层，定义两个业务逻辑层对象：ProfessionInfoBLL proBll = new ProfessionInfoBLL(); StudentInfoBLL stuBll = new StudentInfoBLL();（3）查询窗体绑定专业信息、绑定学生信息以及搜索功能代码：#region 绑定下拉框 private void BindPro() { List<ProfessionInfoEntity> list = new List<ProfessionInfoEntity>(); list = proBll.List(); list.Insert(0,new ProfessionInfoEntity { ProfessionID=0,ProfessionName="--请选择--"}); this.cmbPro.DataSource = list; this.cmbPro.DisplayMember = "ProfessionName"; this.cmbPro.ValueMember = "ProfessionID"; } #endregion #region 绑定学生数据 private void BindData() { StudentInfoEntiy searchObj = new StudentInfoEntiy(); searchObj.ProfessionID = int.Parse(this.cmbPro.SelectedValue.ToString()); searchObj.StuName = this.txtName.Text; this.dataGridView1.AutoGenerateColumns = false; this.dataGridView1.DataSource = stuBll.Search(searchObj); } #endregion #region 窗体加载 private void FrmSelect_Load(object sender, EventArgs e) { BindPro(); BindData(); } #endregion #region 搜索按钮 private void btSearch_Click(object sender, EventArgs e) { BindData(); } #endregion（4）删除菜单代码：private void 删除ToolStripMenuItem_Click(object sender, EventArgs e) { //添加是否确定删除的对话框 DialogResult result = MessageBox.Show("确定要删除数据吗，删除之后无法恢复！", "提示框", MessageBoxButtons.OKCancel, MessageBoxIcon.Question); if (result == DialogResult.Cancel) return; string stuid = this.dataGridView1.SelectedRows[0].Cells[0].Value.ToString(); if(stuBll.Delete(stuid) == 1) MessageBox.Show("删除成功!"); else MessageBox.Show("删除失败!"); BindData(); }新增窗体界面及代码：ProfessionInfoBLL proBll = new ProfessionInfoBLL(); StudentInfoBLL stuBll = new StudentInfoBLL(); #region 绑定下拉框 private void BindPro() { List<ProfessionInfoEntity> list = new List<ProfessionInfoEntity>(); list = proBll.List(); list.Insert(0, new ProfessionInfoEntity { ProfessionID = 0, ProfessionName = "--请选择--" }); this.cmbPro.DataSource = list; this.cmbPro.DisplayMember = "ProfessionName"; this.cmbPro.ValueMember = "ProfessionID"; } #endregion private void FrmAdd_Load(object sender, EventArgs e) { BindPro(); } private void btAdd_Click(object sender, EventArgs e) { //性别处理 string sex = ""; if (this.rbBoy.Checked == true) sex = this.rbBoy.Text; if (this.rbGirl.Checked == true) sex = this.rbGirl.Text; //爱好处理 string hobby = ""; foreach (CheckBox ck in this.panel2.Controls) { if (ck.Checked == true) { if (!hobby.Equals("")) hobby += ","; hobby += ck.Text; } } StudentInfoEntiy entity = new StudentInfoEntiy(); entity.StuID = this.txtId.Text; entity.StuName = this.txtName.Text; entity.StuAge = int.Parse(this.txtAge.Text); entity.StuSex = sex; entity.StuHobby = hobby; entity.ProfessionID = int.Parse(this.cmbPro.SelectedValue.ToString()); if (stuBll.Add(entity) == 1) MessageBox.Show("新增成功!"); else MessageBox.Show("新增失败!"); this.Close(); }编辑修改窗体界面及代码：public string StuID { get; set; } //学生编号 ProfessionInfoBLL proBll = new ProfessionInfoBLL(); StudentInfoBLL stuBll = new StudentInfoBLL(); #region 绑定下拉框 private void BindPro() { List<ProfessionInfoEntity> list = new List<ProfessionInfoEntity>(); list = proBll.List(); list.Insert(0, new ProfessionInfoEntity { ProfessionID = 0, ProfessionName = "--请选择--" }); this.cmbPro.DataSource = list; this.cmbPro.DisplayMember = "ProfessionName"; this.cmbPro.ValueMember = "ProfessionID"; } #endregion #region 绑定详情 private void BindDetail() { StudentInfoEntiy entity = new StudentInfoEntiy(); entity = stuBll.Detail(this.StuID); this.txtId.Text = entity.StuID; this.txtName.Text = entity.StuName; this.txtAge.Text = entity.StuAge.ToString(); this.cmbPro.SelectedValue = entity.ProfessionID; //性别处理 if (entity.StuSex.Equals("男")) this.rbBoy.Checked = true; else this.rbGirl.Checked = true; //爱好处理 string[] arrHobby = entity.StuHobby.Split(','); foreach (string hobby in arrHobby) { foreach (CheckBox ck in this.panel2.Controls) { if (ck.Text.Equals(hobby)) ck.Checked = true; } } } #endregion private void FrmEdit_Load(object sender, EventArgs e) { BindPro(); BindDetail(); } private void btUpdate_Click(object sender, EventArgs e) { //性别处理 string sex = ""; if (this.rbBoy.Checked == true) sex = this.rbBoy.Text; if (this.rbGirl.Checked == true) sex = this.rbGirl.Text; //爱好处理 string hobby = ""; foreach (CheckBox ck in this.panel2.Controls) { if (ck.Checked == true) { if (!hobby.Equals("")) hobby += ","; hobby += ck.Text; } } StudentInfoEntiy entity = new StudentInfoEntiy(); entity.StuID = this.txtId.Text; entity.StuName = this.txtName.Text; entity.StuAge = int.Parse(this.txtAge.Text); entity.StuSex = sex; entity.StuHobby = hobby; entity.ProfessionID = int.Parse(this.cmbPro.SelectedValue.ToString()); if (stuBll.Update(entity) == 1) MessageBox.Show("修改成功!"); else MessageBox.Show("修改失败!"); this.Close(); }查询窗体中"新增"和"编辑"按钮代码：private void btAdd_Click(object sender, EventArgs e) { FrmAdd frm = new FrmAdd(); frm.Show(); } private void btEdit_Click(object sender, EventArgs e) { string stuid = this.dataGridView1.SelectedRows[0].Cells[0].Value.ToString(); FrmEdit frm = new FrmEdit(); frm.StuID = stuid; frm.Show(); }本文来自博客园，作者：码农阿亮，转载请注明原文链接：https://www.cnblogs.com/wml-it/p/15967883.html

csharp调用OCR和DDDDOCR的DLL进行验证码识别 一、方式1：使用OCR.dll参考了一下精易论坛的这个易语言版的例程:https://bbs.125.la/forum.php?mod=viewthread&tid=14273813效果图：工具类代码：public class OCR { [DllImport("ocr.dll", EntryPoint = "init")] public static extern int Init(); [DllImport("ocr.dll", EntryPoint = "ocr")] public extern static string ocr(byte[] img, int imgLength); } }将ocr.dll放在项目工程的bin\Debug目录下即可。Winform程序中使用：// 1.OCR初始化,全局初始化一次即可,建议放在Program.cs的Main方法中 OCR.Init(); // 2.请求验证码图片 byte[] tmp = "https://passport2.chaoxing.com/num/code" .WithHeader("User-Agent", Constant.USER_AGENT) .WithCookies(out cookies) .GetBytesAsync().Result; // 3.调用DLL进行识别 code = OCR.ocr(tmp, tmp.Length);分流下载链接：{cloud title="OCR.DLL和易语言调用例程" type="bd" url="https://pan.baidu.com/s/1mmHUKscFIMghlm0l7ADS-A?pwd=xq82 " password="xq82 "/}二、方式2：使用DDDDOCR之前写过一篇python调用这个库的文章:记录一次调用OCR验证码识别库的过程,识别率不是很高,最终没有采用今天看到网络上有大神打成了DLL包:ddddocr 单dll版本,记录一下使用，算是多一种验证码的解决方案。效果图:工具类代码：public class OCR { [DllImport("ddocr_qs.dll", EntryPoint = "InitModel")] public static extern int Init(int threadnum); [DllImport("ddocr_qs.dll", EntryPoint = "Identify")] public extern static string ocr(byte[] img, int length); [DllImport("ddocr_qs.dll", EntryPoint = "FreeModel")] public extern static void FreeModel(); } }将ddocr_qs.dll放在项目工程的bin\Debug目录下即可。Winform程序中使用：// 1.OCR初始化,全局初始化一次即可,建议放在Program.cs的Main方法中 // 这里的参数是Thread Number OCR.Init(1); // 2.请求验证码图片 byte[] tmp = "https://passport2.chaoxing.com/num/code" .WithHeader("User-Agent", Constant.USER_AGENT) .WithCookies(out cookies) .GetBytesAsync().Result; // 3.调用DLL进行识别 code = OCR.ocr(tmp, tmp.Length);{cloud title="DDDDOCR_DLL和易语言调用例程" type="bd" url="https://pan.baidu.com/s/1yqY8uTIieeicYt2yow9ogw?pwd=py1l " password="py1l "/}三、附：查看DLL中的可用函数本小白第一次在csharp中调用DLL中的函数,刚拿到OCR.dll后不知道怎么写调用的代码于是上网查了一下,有推荐使用Dependency和Dependencies这两个工具,都有下载使用,感觉上还是后者更强打开GUI界面后直接将OCR.DLL拖入,可以看到函数名这样子但是参数和类型是看不到的 = =,似乎只能问开发者中获取引用1.C#调用论坛发布过的一个OCR.dll崩溃(易语言调用没问题)：https://bbs.125.la/forum.php?mod=viewthread&tid=14451756&highlight=ocr.dll2.几百种网站的本地验证码识别源码(字母和数字通杀):https://bbs.125.la/forum.php?mod=viewthread&tid=142738133.ddddocr 单dll版本https://bbs.125.la/forum.php?mod=viewthread&tid=147328384.好工具推荐系列：VC++开发必备神器 -- Dependencies，查看依赖库DLL，支持win10，比depends更好用:https://blog.csdn.net/libaineu2004/article/details/896707265.Dependency Walker 2.2:http://www.dependencywalker.com/6.Dependencies GITHUB : https://github.com/lucasg/Dependencies

搞明白C#的Async和Await 本文参考： bilibili视频{bilibili bvid="BV1b54y1J72M" page=""/}讲的非常棒！{dotted startColor="#ff6c6c" endColor="#1989fa"/}需求引入 - 下载数据从不同的网站中下载很大的数据量，并且将数据结果呈现在UI客户端的一个经典的实际场景界面代码public partial class Form1 : Form { private readonly HttpClient httpClient = new HttpClient(); public Form1() { InitializeComponent(); } }界面中有一个同步下载按钮(SyncDownload)、异步下载按钮(AsyncDownload)、信息输出的文本框常量类public class Contents { public static readonly IEnumerable<string> WebSites = new string[] { "https://www.zhihu.com", "https://www.baidu.com", "https://www.weibo.com", "https://www.stackoverflow.com", "https://docs.microsoft.com", "https://docs.microsoft.com/aspnet/core", "https://docs.microsoft.com/azure", "https://docs.microsoft.com/azure/devops", "https://docs.microsoft.com/dotnet", "https://docs.microsoft.com/dynamics365", "https://docs.microsoft.com/education", "https://docs.microsoft.com/enterprise-mobility-security", "https://docs.microsoft.com/gaming", "https://docs.microsoft.com/graph", "https://docs.microsoft.com/microsoft-365", "https://docs.microsoft.com/office", "https://docs.microsoft.com/powershell", "https://docs.microsoft.com/sql", "https://docs.microsoft.com/surface", "https://docs.microsoft.com/system-center", "https://docs.microsoft.com/visualstudio", "https://docs.microsoft.com/windows", "https://docs.microsoft.com/xamarin" }; }一、同步下载/// 输出显示 private void ReportResult(string result) { Result.Text += result; } /// 同步下载按钮被单击 private void SyncDownload_Click(object sender, EventArgs e) { // 同步下载按钮点击后执行的代码 Result.Text = ""; // 为了测量程序的执行时间 var stopwatch = Stopwatch.StartNew(); // 启动下载的主函数 DownloadWebsitesSync(); // 输出函数执行的耗时情况 Result.Text += $"Elapsed time: {stopwatch.Elapsed}{Environment.NewLine}"; } /// 遍历所有站点 private void DownloadWebsitesSync() { foreach(var site in Contents.WebSites) { var result = DownloadWebSiteSync(site); ReportResult(result); } } /// 访问网站获取源代码 private string DownloadWebSiteSync(string url) { var response = httpClient.GetAsync(url).GetAwaiter().GetResult(); var responsePayloadBytes = response.Content.ReadAsByteArrayAsync().GetAwaiter().GetResult(); return $"Finish downloding data from {url}. Total bytes returned {responsePayloadBytes.Length}. {Environment.NewLine}"; }测试Finish downloding data from https://www.zhihu.com. Total bytes returned 35556. Finish downloding data from https://www.baidu.com. Total bytes returned 9508. Finish downloding data from https://www.weibo.com. Total bytes returned 0. Finish downloding data from https://www.stackoverflow.com. Total bytes returned 173712. Finish downloding data from https://docs.microsoft.com. Total bytes returned 132907. Finish downloding data from https://docs.microsoft.com/aspnet/core. Total bytes returned 90052. Finish downloding data from https://docs.microsoft.com/azure. Total bytes returned 428349. Finish downloding data from https://docs.microsoft.com/azure/devops. Total bytes returned 86931. Finish downloding data from https://docs.microsoft.com/dotnet. Total bytes returned 79622. Finish downloding data from https://docs.microsoft.com/dynamics365. Total bytes returned 56803. Finish downloding data from https://docs.microsoft.com/education. Total bytes returned 39267. Finish downloding data from https://docs.microsoft.com/enterprise-mobility-security. Total bytes returned 31372. Finish downloding data from https://docs.microsoft.com/gaming. Total bytes returned 61895. Finish downloding data from https://docs.microsoft.com/graph. Total bytes returned 45606. Finish downloding data from https://docs.microsoft.com/microsoft-365. Total bytes returned 68829. Finish downloding data from https://docs.microsoft.com/office. Total bytes returned 68829. Finish downloding data from https://docs.microsoft.com/powershell. Total bytes returned 57777. Finish downloding data from https://docs.microsoft.com/sql. Total bytes returned 55297. Finish downloding data from https://docs.microsoft.com/surface. Total bytes returned 40182. Finish downloding data from https://docs.microsoft.com/system-center. Total bytes returned 43407. Finish downloding data from https://docs.microsoft.com/visualstudio. Total bytes returned 31543. Finish downloding data from https://docs.microsoft.com/windows. Total bytes returned 27177. Finish downloding data from https://docs.microsoft.com/xamarin. Total bytes returned 56064. Elapsed time: 00:00:50.6908524缺点：使用了Foreach循环遍历网站请求数据占用了UI界面刷新的主线程，造成了UI刷新线程的阻塞在函数执行过程中，界面无法拖动，无法互动，用户体验效果差耗时50秒,由于是一个一个网址去请求，所以需要等待一个完成或失败后再去进行下一个请求，执行速度较慢！二、异步下载(一)-异步下载/// 异步下载按钮被单击 private void AsyncDownload_Click(object sender, EventArgs e) { Result.Text = ""; var stopwatch = Stopwatch.StartNew(); DownloadWebsitesAsync(); Result.Text += $"Elapsed time: {stopwatch.Elapsed}{Environment.NewLine}"; } /// 使用 async 用于提醒编译器 该方法中使用到了 Await 关键字 /// 对于希望使用Async和Await关键字的方法，返回值必须是Task或者是Task泛型 private async Task DownloadWebsitesAsync() { foreach (var site in Contents.WebSites) { var result = await Task.Run(() => DownloadWebSiteSync(site)); ReportResult(result); } }测试AsyncDownload_Click中并没有等待DownloadWebSitesAsync执行结束就打印了最后的执行时间相当于DownloadWebSitesAsync被忽略了。修改/// 异步下载按钮被单击 private async void AsyncDownload_Click(object sender, EventArgs e) { Result.Text = ""; var stopwatch = Stopwatch.StartNew(); await DownloadWebsitesAsync(); Result.Text += $"Elapsed time: {stopwatch.Elapsed}{Environment.NewLine}"; }总结经过如上编写，发现在测试异步下载时，UI界面线程不会阻塞，可以在下载时与界面进行交互。通过对比同步和异步两种下载方式，发现两者下载速度并没有太大差别。于是我们可以发现仅仅使用async和await并不能够提升我们处理数据的速度,给我们带来的仅仅是这个UI的响应更加及时。三、异步下载(二)-并发下载在上一节分发下载任务时，使用的是foreach进行遍历网址列表，逐个进行下载数据。虽然Ui Thread并没有被阻塞，但这并没有改变下载数据的策略，数据还是需要从这些网站中一个一个的下载。这样其实就很好理解，为什么在异步的模型中下载数据的时间总时长并没有被缩短。如果想缩短下载所有数据的总时间，那么就需要引入： 并行下载 即我们需要更多的线程并发的从这些网站中下载数据。/// 分发下载任务的主函数 private async Task DownloadWebsitesAsync() { /// 用于存储所有的Task List<Task<string>> downloadWebsiteTasks = new List<Task<string>>(); /// 将原来的下载完成一个再进行下一个，改成快速遍历所有站点，将每一个下载任务存入集合，集合中所有元素并发进行下载。 foreach (var site in Contents.WebSites) { downloadWebsiteTasks.Add(Task.Run(() => DownloadWebSiteSync(site))); } // 当集合所有任务都完成时，统一拿到Result Array<string>返回值 var results = await Task.WhenAll(downloadWebsiteTasks).Result; // 将所有results 全部打印出去。 foreach(var result in results) { ReportResult(result); } }注意：每次程序的第一次完成IO操作时，尤其是这种多线程从远端服务器需要用http下载数据，程序往往会经历一些冷启动的现象，原因是因为我们的 CLR 需要创建相应的Thread Pool来初始化Thread，而初始化每一个Thread也是需要时间的，并且完成这些Http Connection的TCP Connection的建立也是需要时间的。因此程序运行的第一次下载耗时不太稳定，会花费额外的时间，如果想要查看稳定的数据下载，需要多次Run一下这个实验的结果。测试观测到 异步下载+并行下载的时间稳定在2s左右修改减少由于初始化很多线程而造成的速度不稳定冷启动时间/// 访问网站获取源代码 更改为异步操作,命名遵循范式 private async Task<string> DownloadWebSiteAsync(string url) { var response = await httpClient.GetAsync(url); // 直接调用异步方法 var responsePayloadBytes = await response.Content.ReadAsByteArrayAsync(); // 直接调用异步方法 return $"Finish downloding data from {url}. Total bytes returned {responsePayloadBytes.Length}. {Environment.NewLine}"; } private async Task DownloadWebsitesAsync() { List<Task<string>> downloadWebsiteTasks = new List<Task<string>>(); foreach (var site in Contents.WebSites) { // 这时候不需要一个额外的Thread来进行等待 // 所以不再需要Tash.Run，可以直接调用方法。 downloadWebsiteTasks.Add(DownloadWebSiteAsync()); } var results = await Task.WhenAll(downloadWebsiteTasks).Result; foreach(var result in results) { ReportResult(result); } }程序运行后的第一次下载：耗时2s

.NET项目连接虚拟机VMware的SQL Server 不太喜欢Visual Studio和SQL Server，体积太大了，但是想以后桌面程序使用WPF或Winform开发，所以还是下回来了，顺便临近毕业了，大一大二挂科的都要清考不然毕业证拿不了，有同学的ASP.NET MVC挂了 我决定！捞一把....1.下载1.1 下载VsVs没得说,直接下载到主机 这里下的2022 latest version,不得不说 2022年的这版和Jetbrains系列的软件颜值都上升了有个小坑，使用vs installer默认不会携带.net framework的 MVC，需要自己勾选一下：1.2 下载SQLServer使用的是SQL Server2012,在学校上课的时候用的就是这个版本，害 反正就是CRUD，版本差别不大推个下载地址:{cloud title="SQL Server 2012最新版" type="default" url="https://www.onlinedown.net/soft/1229604.htm" password=""/}顺便附一个密钥[MICROSOFT SQL SERVER 2012 DEVELOPER 版序列号]：YQWTX-G8T4R-QW4XX-BVH62-GP68Y MICROSOFT.2022/05/25亲测可用1.3 安装Win7镜像::(泪) 安装了Vs后再安装SQL Server发现安装路径不能改变！！但是C盘又没有容量了，只好装个虚拟机了不过好在还发现了一个下载镜像的网站： https://next.itellyou.cn/ ，都是纯净版的，同样也是没有激活的。需要登录才能访问，也可以直接下载下方我提供的 Windows 7 Ultimate with Service Pack 1 (x64) - DVD (Chinese-Simplified)magnet:?xt=urn:btih:E86414F638E11104248108B155BE9408A8362509&dn=cn_windows_7_ultimate_with_sp1_x64_dvd_u_677408.iso&xl=34205573121.4 Navicat平常用的都是MySQL+SQLYog,发现Navicat可以连接SQLServer,那就不用切换到虚拟机了，果然整一个分享一个15.0.17版本的：{cloud title="Premium免安装版本，内附注册机" type="bd" url="https://pan.baidu.com/s/1sCXzwzA6fRtskNP8nKPO0w?pwd=p5sf " password="p5sf"/}2.主机连接虚拟机SQL Server这步就很烦，主机和虚拟机可以互相Ping通但就是连接不上，最后依照以下步骤解决问题.原文链接： https://blog.csdn.net/qq_33454111/article/details/885405211.首先保证主机和虚拟机互相能ping通​如果不能ping通，可能是防火墙的问题，需要开启相应的入站规则。2.主机telnet虚拟机的1433端口如果出现黑屏，则表示连接得上如果连接不上，则在虚拟机中添加入站规则3.在虚拟机中登陆想要在主机登陆的账号4.开启允许远程连接到此服务器选项5.设置RemoteAccessEnabled属性为true6.修改sql server配置管理器属性配置完成后需要重新启动服务7.主机连接虚拟机sql server,图上的端口可加可不加3.编写程序项目中的数据库操作要求使用EntityFramework,数据库连接字符串： <connectionStrings> <!-- 连接本机的SQL Server --> <add name="conn" connectionString="Server=.;DataBase=Photography;Trusted_Connection=True;" providerName="System.Data.SqlClient" /> <!-- 连接服务器/虚拟机的SQL Server --> <add name="conn" connectionString="Server=192.168.191.129;DataBase=Photography;user id=sa;password=123456;" providerName="System.Data.SqlClient" /> </connectionStrings>留个小demo,以后再写.net估计就忘的差不多了，方便参考参考{cloud title="EF+IOC示例" type="bd" url="https://pan.baidu.com/s/1P8y5FrN6rqKv_iBUI2U05g?pwd=818f " password="818f"/}