Question

在我尝试在SQL DATAMANAGEMENT STUDIO中将identity_insert设置为ON时发生。

最糟糕的是我不知道为什么要处理这个值，我甚至不确定以下代码是否比本地内存中的数据库副本更多。

当调试到达SaveChanges行时，我之前收到此消息： “当IDENTITY_INSERT设置为OFF时，无法在表'tblCustomer'中为标识列插入显式值”

    ` public ActionResult Submit( 
    Customer obj) //validation runs 
    { 

        if (ModelState.IsValid)
        {
            CustomerDal Dal = new CustomerDal();
            Dal.Customer.Add(obj);     //in memory
            Dal.SaveChanges();          //physical commit 

            return View("Customer", obj);
        }
        else
        { 
            return View("EnterCustomer", obj);
        }
    }`

    public class Customer
{
    [Key]
    [Required]
    [DatabaseGenerated(DatabaseGeneratedOption.none)]
    public string CustomerCode { get; set; }

    [Required]
    [StringLength(10)]
    [RegularExpression("^[A-Z]{7,7}$")]
    public string CustomerName { get; set; }
}

    public class CustomerDal : DbContext 
{
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<Customer>().ToTable("tblCustomer");
    }

    public DbSet<Customer> Customer { get; set; }

}

CREATE TABLE [dbo].[tblCustomer]( [CustomerCode] [varchar](50) NOT NULL, [CustomerName] [varchar](50) NULL, CONSTRAINT [PK_tblCustomer] PRIMARY KEY CLUSTERED ( [CustomerCode] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY]

    @using (Html.BeginForm("Submit", "Customer", FormMethod.Post))
    {

        <i>Customer Name : </i> @Html.TextBoxFor(m => m.CustomerName)

    <br>
    @Html.ValidationMessageFor(x => x.CustomerName)
    <br>

        <i>Customer Code : </i> @Html.TextBoxFor(m => m.CustomerCode)

            <br>
            @Html.ValidationMessageFor(x => x.CustomerCode)
            <br>
            <input id = "Submit1" type = "submit" value = "submit"/>

            }

Answer 1

假设您的表 tblCustomer 有一个标识列，并假设您使用标记配置映射，请为标识属性指定 DatabaseGenerated ：

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

如果您在yout表上没有标识列，请将其设置为无。

[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int Id { get; set; }

https://msdn.microsoft.com/en-us/library/jj591583(v=vs.113).aspx

您能否提供有关表格和EF映射的更多详细信息？

表'tblCustomer'没有identity属性。无法执行SET操作

1 个答案: