ASP.NET MVC Notes

1. inetmgr 进入IIS
2. ViewBag和ViewData在run-time的时候检查错误，View中的用法如下： 

3.    @*ViewBag传递的是动态对象*@
       @foreach (string item in ViewBag.listData)
       {
           <li>@item</li>
       }
       -----------------------------------------
       @*ViewData传递的是Object,所以要转换类型*@
       @foreach (string item in (List<string>)ViewData["Countries"])
       {
           <li>@item</li>
       }

4. web.config中连接字符串名称需要和DbContext的类名称一致：

5. public class EmployeeContext : DbContext
       {
           //定义对应到数据库表的对象集合
           public DbSet<Employee> Employees { get; set; }
       }
   
       <add name="EmployeeContext"
            providerName="System.Data.SqlClient"
            connectionString="Data Source=.;Initial Catalog=MVCSample;User ID= ;Password= ; "  />

6. Global.ashx 程序运行初始化配置：

7. //DBFirst从数据读取数据，程序运行的时候EmployeeContext初始化为Null
       Database.SetInitializer<MVCBlog.Models.EmployeeContext>(null);

8. View需要List数组对象，则强类型直接定义为IEnumerable; View中@using引用需要用到的类 

9. @model IEnumerable<MVCBlog.Models.Employee>
   @using MVCBlog.Models
   
   @{
       ViewBag.Title = "Index";
       Layout = "~/Views/Shared/_Layout.cshtml";
   }
   
   <h2>Index</h2>
   
   @*Controller 传递过来的是List对象,所以强类型定义为List<MVCBlog.Models.Employee>*@
   <ul>
       @foreach (Employee employee in @Model)
       {
           <li> @Html.ActionLink(employee.Name, "Details", new { @id = @employee.EmployeeID })  </li>
       }
   </ul>

10. 业务逻辑层获取数据

11. public IEnumerable<Employee> employees
            {
                get
                {
                    string connectionString = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
    
                    List<Employee> employees = new List<Employee>();
    
                    using (SqlConnection con = new SqlConnection(connectionString))
                    {
    
                        SqlCommand cmd = new SqlCommand("sp_GetAllEmployee", con);
                        cmd.CommandType = CommandType.StoredProcedure;
                        con.Open();
                        SqlDataReader sdr = cmd.ExecuteReader();
                        while (sdr.Read())
                        {
                            Employee employee = new Employee();
                            employee.EmployeeID = Convert.ToInt32(sdr["EmployeeID"]);
                            employee.Name = sdr["Name"].ToString();
                            employee.City = sdr["City"].ToString();
                            employee.Gender = Convert.ToChar(sdr["Gender"]); 
    
                            employees.Add(employee);
                        }
                        return employees;
                    }
                }
            }

12. Razor中构建DropList:

13.   @Html.DropDownList("Gender", new List<SelectListItem> {
                          new SelectListItem { Text="男",Value="M"},
                          new SelectListItem{ Text="女",Value="F"}
                    }, "Select Gender", htmlAttributes: new { @class = "control-label col-md-2" })
      //或者是在Controller中构建SelectList后，Razor中Render
      ViewBag.DepartID = new SelectList(db.Department, "ID", "Name", employee.DepartID); 
    
      @Html.DropDownList("DepartID", null, "Select Department",htmlAttributes: new { @class = "form-control" })

14. Procedure AddEmployee

15. CREATE PROCEDURE sp_AddEmployee
         @Name nvarchar(50)=null,
         @Gender char(1)=null,
         @City nvarchar(50)=null,
         @DateOfBirth DateTime=null
    AS
    BEGIN
        -- SET NOCOUNT ON added to prevent extra result sets from
        -- interfering with SELECT statements.
        Insert Into Employee(Name,Gender,City,DateOfBirth)
        values(@Name,@Gender,@City,@DateOfBirth)
    END
    GO

16. Controller搜集从View页面Post过来的数据，有三种方法：
    1. FormCollection 中包含了所有表单数据的键值对集合，通过FromCollection[Key] 访问到View Post 过来的 Data

       1.  [HttpPost]
                  public ActionResult Create(FormCollection formCollection)
                  {
                      //foreach (string key in formCollection.AllKeys)
                      //{
                      //    Response.Write(key + " "); 
                      //    Response.Write(formCollection[key] + "<br/>");
                      //}
          
                      Employee employee = new Employee();
                      employee.Name = formCollection["Name"];
                      employee.Gender = Convert.ToChar(formCollection["Gender"]);
                      employee.City = formCollection["City"];
                      employee.DateOfBirth = Convert.ToDateTime(formCollection["DateOfBirth"]);
          
                      EmployeeService employeeService = new EmployeeService();
                      int numSucc = employeeService.AddEmployee(employee);
          
                      if (numSucc > 0)
                      {
                          return RedirectToAction("Index");
                      }
                      else
                      {
                          return View();
                      } 
                  }

    2. 直接以参数的形式接收数据

       1.  [HttpPost]
                  public ActionResult Create(string Name,char Gender,string City,string DateOfBirth)
                  { 
                      Employee employee = new Employee();
                      employee.Name = Name;
                      employee.Gender = Gender;
                      employee.City = City;
                      employee.DateOfBirth = Convert.ToDateTime(DateOfBirth);
          
                      EmployeeService employeeService = new EmployeeService();
                      int numSucc = employeeService.AddEmployee(employee);
          
                      if (numSucc > 0)
                      {
                          return RedirectToAction("Index");
                      }
                      else
                      {
                          return View();
                      }
                  }

    3. Controller中UpdaetModel 更新 Model，获得提交过来的数据 

       1.  [HttpPost]
                  [ActionName("Create")]
                  public ActionResult Create_Post()
                  {
                      Employee employee = new Employee();
                      UpdateModel<Employee>(employee);
          
                      int numSucc = 0;
                      if (ModelState.IsValid)
                      {
                          EmployeeService employeeService = new EmployeeService();
                          numSucc = employeeService.AddEmployee(employee);
                      } 
          
                      if (numSucc > 0)
                      {
                          return RedirectToAction("Index");
                      }
                      else
                      {
                          return View();
                      }
                  }

17. Service  新增数据服务：

    1. public int AddEmployee(Employee employee)
               {
                   int numSucc = 0;
                   using (SqlConnection conn = new SqlConnection(connectionString))
                   {
                       SqlCommand cmd = new SqlCommand("sp_AddEmployee", conn);
                       cmd.CommandType = CommandType.StoredProcedure;
                       SqlParameter[] paras = new SqlParameter[] {
                           new SqlParameter("Name",employee.Name),
                           new SqlParameter("Gender",employee.Gender),
                           new SqlParameter("City",employee.City),
                           new SqlParameter("DateOfBirth",employee.DateOfBirth)
                       };
                       cmd.Parameters.AddRange(paras);
       
                       conn.Open();
                       numSucc = cmd.ExecuteNonQuery();
                   }
       
                   return numSucc;
               }

18. 解决方案中的Nuget包管理器对解决方案中的Nuget包进行管理。

19. Controller中模型绑定的两种方法：
    1,Bind 制定需要进行模型绑定传递到Controller中的数据。

    public ActionResult Edit_Post([Bind(Include = "Gender , City,DateOfBirth")]Employee employee)

    2，在UpdateModel中，传递需要更新或者是不需要更新的参数

    UpdateModel<Employee>(employee, null, null, new string[] { "Name" });

    3，定义IEmployee接口，Employee继承自IEmployee.

    UpdateModel<IEmployee>(employee);

20. 进行数据的Delete动作必须在Post数据中执行

    1.   @foreach (var item in Model)
           {
               using (Html.BeginForm("Delete", "Employee", new { id = item.ID }))
               {
                   <tr>
                       <td>
                           @Html.DisplayFor(modelItem => item.Name)
                       </td>
                       <td>
                           @Html.DisplayFor(modelItem => item.Gender)
                       </td>
                       <td>
                           @Html.DisplayFor(modelItem => item.City)
                       </td>
                       <td>
                           @Html.DisplayFor(modelItem => item.DateOfBirth)
                       </td>
                       <td>
                           @Html.ActionLink("Edit", "Edit", new { id = item.ID }) |
                           @Html.ActionLink("Details", "Details", new { id = item.ID }) | 
                           <input type="submit" value="Delete"  onclick="return confirm('确定删除 @item.Name 吗 ')" />
                       </td>
                   </tr>
               }
           }

21. EF中字段属性的控制，如：[Required]、[Display(Name="")]  需在partial class中进行处理

    1. [MetadataType(typeof(EmployeeMetaData))]
           public partial class Employee
           {
       
           }
           public class EmployeeMetaData
           {
               [Required]
               [Display(Name = "姓名")]
               public string Name { get; set; }
       
               [Required]
               [Display(Name = "性别")]
               public char Gender { get; set; }
       
               [Required]
               [Display(Name = "所在城市")]
               public string City { get; set; }
       
               [Required]
               [Display(Name = "生日")]
               public DateTime DateOfBirth { get; set; }
                
               [Required]
               [Display(Name = "部门")]
               public int DepartID { get; set; } 
           }

22. Edit信息的时候不需要更新字段的处理，如不需要更新Name。
    1. partial class 中 去掉 [Required]
    2. Edit方法中用 查出来的实体来存储更新后的数据

    3.  [HttpPost]
               [ValidateAntiForgeryToken]
               public ActionResult Edit([Bind(Include = "ID,Gender,City,DateOfBirth,DepartID")] Employee employee)
               {
                   Employee employeeFromDB = db.Employee.Find(employee.ID);
       
                   //须要用你查出来的实体来存储更新后的数据，不更新Name字段
                   employeeFromDB.City = employee.City;
                   employeeFromDB.Gender = employee.Gender;
                   employeeFromDB.DepartID = employee.DepartID;
                   employeeFromDB.DateOfBirth = employee.DateOfBirth;
       
                   if (ModelState.IsValid)
                   {
                       db.Entry(employeeFromDB).State = EntityState.Modified;
                       db.SaveChanges();
                       return RedirectToAction("Index");
                   }
                   ViewBag.DepartID = new SelectList(db.Department, "ID", "Name", employee.DepartID);
                   return View(employee);
               }

    4. Controller的Create方法中必需的字段，添加验证检查处理

    5.  if (string.IsNullOrEmpty(employee.Name))
                   {
                       ModelState.AddModelError("Name", "姓名为必需字段");
                   }

23. Lambda表达式，统计Department下Employee数量

    1.  [HttpGet]
               public ActionResult EmployeeByDepartment()
               {
                   var departmentTotals = db.Employee.Include("Department")
                       .GroupBy(d => d.Department.Name)
                       .Select(y => new DepartmentTotals
                       {
                           Name = y.Key,
                           Total = y.Count()
                       }).ToList().OrderByDescending(y => y.Total);
       
                   return View(departmentTotals);
               }

24. Controller中Return View()中如果指定带有后缀的View,如index.cshtml，则需要传递完整路径：

    1.  public ActionResult Index()
               {
                   var employee = db.Employee.Include(e => e.Department);
                   return View("~/Views/Employee/Index.cshtml",employee.ToList());
               }