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