ASP.NET MVC Notes - 01

   @*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>
    }

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= ; "  />

//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);

@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>

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;
                }
            }
        }

  @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" })

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

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();
                  }
              }

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;
           }

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);

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>
           }
       }

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; }
       }

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");
               }

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);
           }

1. 

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