Getting Error: Cannot insert explicit value for identity column in table 'Table' when IDENTITY_INSERT is set to OFF

Question

我有简单的DataTable

CREATE TABLE [dbo].[Table] (
[Id]   INT        IDENTITY (1, 1) NOT NULL,
[Name] NCHAR (10) NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);

有一条记录，Name="Test" Id 自动得到 0.

当我使用基本的创建操作时

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Table table)
{
    if (ModelState.IsValid)
    {
        db.Table.Add(table);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    return View(table);
}

我收到错误：

Cannot insert explicit value for identity column in table 'Table' when IDENTITY_INSERT is set to OFF.

我做错了什么？如何修复此错误？

Table class

public partial class Table
{
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public string Name { get; set; }
}

Answer 1

您需要将 IsDbGenerated 设置为 true。然后将 System.Data.Linq 添加到您的参考资料中：

[System.Data.Linq.Mapping.Column(Storage = "Id", DbType = "Int NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)]
public int Id { get; set; }

Answer 2

闻起来像是您从参数 (Table table) 中检索到的 table 正在将属性 Id 设置为 0 之外的其他值.

如果是这种情况，请确保在 db.Table.Add(table);

之前将 Id 设置为 0

如果您想要更新项目（如果它存在），那么您需要在添加之前检查 Id 是否为 0。

if(table.Id == 0)
   db.Table.Add(table);
db.SaveChanges();

Answer 3

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }

这对我有用。

Getting Error: Cannot insert explicit value for identity column in table 'Table' when IDENTITY_INSERT is set to OFF

Getting Error: Cannot insert explicit value for identity column in table 'Table' when IDENTITY_INSERT is set to OFF

c#

sql-server

asp.net

asp.net-mvc

entity-framework-5