代码优先实体框架未保存到数据库

Question

好的，我正在做一个带有实体框架6的项目。 当我尝试将信息添加到数据库时； 它给了我以下错误：

The best overloaded method match for 'System.Data.Entity.DbSet<img_site_codefi.DAL.DefaultConnection>.Add(img_site_codefi.DAL.DefaultConnection)' has some invalid arguments

Argument 1: cannot convert from 'AnonymousType#1' to 'img_site_codefi.DAL.DefaultConnection'

这是我的控制器：

public ActionResult Contact(customer cust)
{
    try
    {
        if (ModelState.IsValid)
        {
            cust.Tele_comp();
            saveIntoDb(cust); // database
            SendMail(cust); // mail sender
            return RedirectToAction("Submited", "Home");
        }
        return null;
    }
    catch (DataException)
    {
        return View(cust);
    }
}

private void saveIntoDb(customer cust)
{
    using (var cust_In = new DefaultConnection())
    { 
        var customer = new {fname = cust.fname,lname = cust.lname, tele = cust.tele, email = cust.email, reasn = cust.reasn };
        //cust_In.customers.Add(customer); //HERE IS THE ERROR!!!
        cust_In.SaveChanges();
    }    
}

这是模型：

    [Key]
    [] // how to assign a number automatically 
    public int Cust_Id { get; set; } 
    [Required(ErrorMessage = "first name is required!")]
    [Display(Name = "First name")]
    public string fname { get; set; }
    [Display(Name = "Last name")]
    public string lname { get; set; }

    [Required(ErrorMessage = "area code is required!")]
    [StringLength(3)]
    [RegularExpression(@"^[0-9]{3,}$", ErrorMessage = "Minimum 3 numbers required & contain only numbers")]
    [Display(Name = "Telephone")]
    public string tel_area { get; set; }

    [Required(ErrorMessage = "first three numbers are required!")]
    [StringLength(3)]
    [RegularExpression(@"^[0-9]{3,}$", ErrorMessage = "Minimum 3 numbers required & contain only numbers")]
    public string fir_thr_tel { get; set; }

    [Required(ErrorMessage = "last four numbers are required!")]
    [StringLength(4)]
    [RegularExpression(@"^[0-9]{4,}$", ErrorMessage = "Minimum 4 numbers required & contain only numbers")]
    public string lst_fur_tel { get; set; }

    [Required(ErrorMessage = "E-mail is required!")]
    [RegularExpression("^[a-zA-Z0-9_\\.-]+@([a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,6}$", ErrorMessage = "E-mail is not valid")]
    [Display(Name = "Email")]
    public string email { get; set; }
    [Required(ErrorMessage = "A reason is required!")]
    [Display(Name = "Reason")]
    public string reasn { get; set; }

    public string tele { get; set; }

另外，如何像SQL数据库IDENTITY或计算的那样为数据库自动为“ Cust_Id”生成一个数字。

Answer 1

您有2个问题。 首先，这一行是错误的：

var customer = new {fname = cust.fname,lname = cust.lname, tele = cust.tele, email = cust.email, reasn = cust.reasn };

您正在创建匿名类型而不是customer对象。 尝试以下方法：

var customer = new customer 
{
    fname = cust.fname,
    lname = cust.lname, 
    tele = cust.tele, 
    email = cust.email, 
    reasn = cust.reasn 
};

其次，您的上下文DefaultConnection错误，并且包含以下内容：

public DbSet<DefaultConnection> customers { get; set; }

您正在创建上下文类的DbSet而不是customer 。 应该是：

public DbSet<customer> customers { get; set; }

Answer 2

您不能将Anonymous类型的类或Dynamic添加到DbSet中，因此您需要创建一个Customer的实例类才能将其添加到DbSet中。

public ActionResult Contact(Customer cust)
{
    try
    {
        if (ModelState.IsValid)
        {
            cust.Tele_comp();
            saveIntoDb(cust); // database
            SendMail(cust); // mail sender
            return RedirectToAction("Submited", "Home");
        }
        return null;
    }
    catch (DataException)
    {
        return View(cust);
    }
}

private void saveIntoDb(Customer cust)
{
    using (var cust_In = new DbContext())
    { 
        var customer = new Customer {fname = cust.fname,lname = cust.lname, tele = cust.tele, email = cust.email, reasn = cust.reasn };
        cust_In.Customers.Add(customer); //HERE IS THE ERROR!!!
        cust_In.SaveChanges();
    }    
}

同样，您的DbContext.cs类应具有以下内容而不是代码：

public DbSet<Customer> Customers { get; set; }

为了生成主键，您应该使用以下命令：

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]

确保首先尝试本教程： http : //msdn.microsoft.com/zh-cn/data/jj572366.aspx