自動增量列.NET

Question

我有一個C＃.NET的Web應用程序，我想創建一個ID的自動增量。我無法弄清楚我做錯了什麼，但是我不斷收到錯誤，因爲它沒有增加。

錯誤：

Cannot insert the value NULL into column 'Id', table 'Samen de Zorg.dbo.BulletinItem'; column does not allow nulls. INSERT fails.
The statement has been terminated.

控制器：

[HttpPost] 
    [ValidateAntiForgeryToken] 
    public ActionResult Create([Bind(Include = "UserID,Title,Description")] BulletinItem bulletinItem) 
    { 
     // 
     if (ModelState.IsValid) 
     { 
      db.BulletinItem.Add(bulletinItem); 
      db.SaveChanges(); 
      return RedirectToAction("Index"); 
     } 

     return View(bulletinItem); 
    } 

型號：

[Key] 
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
    public int Id { get; set; } 
    public string UserID { get; set; } 
    public string Title { get; set; } 
    public string Description { get; set; } 

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")] 
    public virtual ICollection<BulletinReaction> BulletinReaction { get; set; } 

模型XML：

 <EntityType Name="BulletinItem"> 
      <Key> 
      <PropertyRef Name="Id" /> 
      </Key> 
      <Property Name="Id" Type="int" Nullable="false" StoreGeneratedPattern="Identity" /> 
      <Property Name="UserID" Type="nvarchar" MaxLength="256" Nullable="false" /> 
      <Property Name="Title" Type="nvarchar" MaxLength="50" Nullable="false" /> 
      <Property Name="Description" Type="nvarchar(max)" Nullable="false" /> 
     </EntityType> 

模型SQL：

CREATE TABLE [dbo].[BulletinItem] 
(
    [Id]   INT   NOT NULL, 
    [UserID]  NVARCHAR (256) NOT NULL, 
    [Title]  NVARCHAR (50) NOT NULL, 
    [Description] NVARCHAR (MAX) NOT NULL, 

    CONSTRAINT [PK_BulletinItem] 
     PRIMARY KEY CLUSTERED ([Id] ASC), 

    CONSTRAINT [FK_BulletinItem_AspNetUsers] 
     FOREIGN KEY ([UserID]) REFERENCES [dbo].[AspNetUsers] ([UserName]) 
); 

Answer 1

您需要在SQL模型，不僅說不能爲空，但也只是AUTO_INCREMENT添加一個空格其間。