相关疑难解决方法(0)

错误消息:

"自创建数据库以来,支持'AddressBook'上下文的模型已经改变.手动删除/更新数据库,或者使用IDatabaseInitializer实例调用Database.SetInitializer.例如,RecreateDatabaseIfModelChanges策略将自动删除并重新创建数据库,并且可选择用新数据播种."

我正在尝试使用代码优先功能,以下是我写的:

var modelBuilder = new ModelBuilder();
var model = modelBuilder.CreateModel();
using (AddressBook context = new AddressBook(model))
{
    var contact = new Contact
    {
        ContactID = 10000,
        FirstName = "Brian",
        LastName = "Lara",
        ModifiedDate = DateTime.Now,
        AddDate = DateTime.Now,
        Title = "Mr."

    };
    context.contacts.Add(contact);
    int result = context.SaveChanges();
    Console.WriteLine("Result :- "+ result.ToString());
}

上下文类:

public class AddressBook : DbContext
{
    public AddressBook()
    { }
    public AddressBook(DbModel AddressBook)
        : base(AddressBook)
    {

    }
    public DbSet<Contact> contacts { get; set; }
    public …

所以我尝试使用我的新MVC 4项目进行自动迁移,但不知何故它无法正常工作.我一步一步地关注这篇博文.

我已将更改添加到UserProfile帐户模型(NotaryCode字段):

[Table("UserProfile")]
public class UserProfile
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int UserId { get; set; }
    public string UserName { get; set; }
    public int NotaryCode { get; set; }
}

然后我在包管理器控制台上写了enable-migrations一个Configuration类出现(继承自DbMigrationsConfiguration<Web.Models.UsersContext>)然后我将类填充为:

public Configuration()
{
    AutomaticMigrationsEnabled = true;
}

protected override void Seed(Atomic.Vesper.Cloud.Web.Models.UsersContext context)
{
    WebSecurity.InitializeDatabaseConnection(
            "DefaultConnection",
            "UserProfile",
            "UserId",
            "UserName", autoCreateTables: true);

    if (!Roles.RoleExists("Atomic"))
        Roles.CreateRole("Atomic");

    if (!Roles.RoleExists("Protocolista"))
        Roles.CreateRole("Protocolista");

    if (!Roles.RoleExists("Cliente"))
        Roles.CreateRole("Cliente");

    string adminUser = "randolf";

    if (!WebSecurity.UserExists(adminUser))
        WebSecurity.CreateUserAndAccount(
            adminUser, …

您好，我正在尝试将以下 SQL 语句转换为其等效的 LINQ 语句，并且由于我对 .net 真的很陌生（编码了一天），因此我已经被困在这个问题上好几个小时了。

SELECT * 
 FROM Books 
 WHERE BookID IN (SELECT BookID 
              FROM Borrows 
              WHERE UserID = 2) 

这是模型

public class LibUser
{       
    [Key]
    public int UserID { get; set; }
    [Required, StringLength(50), Display(Name = "First Name")]
    public string UserFirstName { get; set; }
    [Required, StringLength(50), Display(Name = "Last Name")]
    public string UserLastName { get; set; }
    [Required, StringLength(10000), Display(Name = "Residence"), DataType(DataType.MultilineText)]
    public string Adress { get; set; }
}

public class Book { 
    [Key] …