Question

我的EF Code First CTP4工作正常，我今天安装了CTP5。现在，我重新填充数据库时出现异常。

这是我的模特：

public class Member
{
    public Member()
    {
        DateCreated = DateTime.Now;
        DateUpdated = DateTime.Now;
        DateLastLogin = DateTime.Now;
    }
    [Key, DatabaseGenerated(DatabaseGenerationOption.Identity)]  \\I have tried removing these annotations and the result is the same
    public int MemberId { get; set; }
    [Required,RegularExpression(".+\\@.+\\..+", ErrorMessage = "Please enter a valid email address")]
    public string Email { get; set; }
    [Required,StringLength(20,MinimumLength=2)]
    public string FirstName { get; set; }
    [Required, StringLength(20, MinimumLength = 2)]
    public string LastName { get; set; }
    [Required, StringLength(36, MinimumLength = 2)]
    public string City { get; set; }
    [Required, StringLength(20, MinimumLength = 2)]
    public string State { get; set; }
    [Required, StringLength(20, MinimumLength = 2)]
    public string Zip { get; set; }
    public double GeoLat { get; set; }
    public double GeoLong { get; set; }
    public string AccountStatus { get; set; }
    public DateTime DateCreated { get; private set; }
    public DateTime DateUpdated { get; set; }
    public DateTime DateLastLogin { get; set; }

    public virtual PublicProfile Profile { get; set; }        
}

以下是在Global.asax.cs中调用的代码

protected void Application_Start()
{           
     RegisterRoutes(RouteTable.Routes);
     DbDatabase.DefaultConnectionFactory = new SqlConnectionFactory("System.Data.SqlClient");
     DbDatabase.SetInitializer<MeetPplDB>(new Initializer());
}

public class Initializer : DropCreateDatabaseAlways<MeetPplDB>
{
    protected override void Seed(MeetPplDB context)
    {
        var Members = new List<Member>
        {
            new Member {
                Email = "dave@dave.com",
                City = "San Francisco",
                AccountStatus = "Active",
                State = "CA",
                FirstName = "David",
                LastName = "Daverson",
                Zip = "94118",
                GeoLat = 37.735,
                GeoLong = -122.392 },

            new Member { 
                Email = "bob@bob.com", 
                City = "Oakland", 
                AccountStatus = "Active", 
                State = "CA", 
                FirstName = "Bob", 
                LastName = "Boberson", 
                Zip = "94601",
                GeoLat = 37.781,
                GeoLong = -122.216 },

           new Member {
               Email = "jenny@jenny.com",
               City = "San Francisco",
               AccountStatus = "Active",
               State = "CA",
               FirstName = "Jenny",
               LastName = "Jennerson",
               Zip = "94123",
               GeoLat = 37.735,
               GeoLong = -122.392 }
        };
        Members.ForEach(m => context.Members.Add(m));
        context.SaveChanges();
     }
}

当它遇到上下文中的SaveChanges时，我得到了这个例外：

检测到冲突的更改。尝试使用相同的密钥插入多个实体时可能会发生这种情况。

描述：执行当前Web请求期间发生了未处理的异常。请查看堆栈跟踪，以获取有关错误及其在代码中的起源位置的更多信息。

异常详细信息：System.Data.UpdateException：检测到冲突的更改。尝试使用相同的密钥插入多个实体时可能会发生这种情况。

有没有人知道发生了什么变化以及为什么这不再起作用了？需要改变什么才能发挥作用？

Answer 1

您的异常的原因是您将数据类型int与DatabaseGenerationOption.Identity结合使用。使用identity将生成一个guid，而不是一个int键。

我有类似的问题，因为我想要一个类型为int的键和一个Guid作为唯一的rowid。如果我在一个实体上使用它们，即使它们在不同的道具中，种子也会停止工作。

Answer 2

可能是因为您使用的变量名已被EF生成为多元化。

而不是：

public class Initializer : DropCreateDatabaseAlways<MeetPplDB>
{
    protected override void Seed(MeetPplDB context)
    {
        var Members = new List<Member>
        {
            new Member {
                Email = "dave@dave.com",
                City = "San Francisco",
.....

试试这个

public class Initializer : DropCreateDatabaseAlways<MeetPplDB>
{
    protected override void Seed(MeetPplDB context)
    {
        var _members = new List<Member>
        {
            new Member {
                Email = "dave@dave.com",
                City = "San Francisco",

....


_members.ForEach(m => context.Members.Add(m));
        context.SaveChanges();

我将您的代码与Scott Gu的代码进行比较 http://weblogs.asp.net/scottgu/archive/2010/07/16/code-first-development-with-entity-framework-4.aspx

EF4 Code First CTP5：种子方法不再有效

2 个答案: