出现错误：当IDENTITY_INSERT设置为OFF时，无法在表'Table'中为标识列插入显式值

Question

I have simple DataTable

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

With one record, Name="Test" Id get's automatic 0.

When I am using basic create operation

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

    return View(table);
}

I get error:

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

What I am doing wrong? How to fix this error?

Table class

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

Answer 1

You need to set IsDbGenerated to true . Add System.Data.Linq to your references then:

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

Answer 2

It smells like the table that you are retrieving from the argument ( Table table ) is setting the property Id to other value than 0 .

If that's the case, be sure that you set the Id to 0 before db.Table.Add(table);

If you want to update the item if it exists, then you need to check if the Id is 0 before adding it.

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

Answer 3

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

This worked for me.