删除时Gridview ObjectDataSource InvalidOperationException

问题描述

|| 我正在学习LINQ / EF，并且已经编写了以下代码片段。创建/读取/更新工作，但是Delete引发InvalidOperationException。当我将鼠标悬停在错误上时，它显示Customer对象的空值。 有什么想法吗？ HTML代码

<asp:GridView ID=\"GridView1\" runat=\"server\" AutoGenerateColumns=\"False\" 
    DataSourceID=\"CustomersODS\">
    <Columns>
        <asp:CommandField ShowDeleteButton=\"True\" ShowEditButton=\"True\" />
        <asp:BoundField DataField=\"ID\" HeaderText=\"ID\" SortExpression=\"ID\" />
        <asp:BoundField DataField=\"Name\" HeaderText=\"Name\" SortExpression=\"Name\" />
    </Columns>
</asp:GridView>
<asp:ObjectDataSource ID=\"CustomersODS\" runat=\"server\" 
    DataObjectTypeName=\"CustOrderTest.Models.Customer\" 
    DeleteMethod=\"Customer_Delete\" SelectMethod=\"Customers_GetAll\" 
    TypeName=\"CustOrderTest.Models.CustomerModel\" UpdateMethod=\"Customer_Update\">
</asp:ObjectDataSource>

方法库

namespace CustOrderTest.Models
{
    public class CustomerModel
    {

        COContext DB = new COContext();

        public List<Customer> Customers_GetAll()
        {
            return (from customer in DB.Customers
                    select customer).ToList();
        }

        public List<Customer> Customers_Search(string CustomerName)
        {
            return (from customer in DB.Customers
                    where customer.Name.Contains(CustomerName)
                    select customer).ToList();
        }

        public Customer Customer_GetByID(int? ID)
        {
            return (from customer in DB.Customers
                    where customer.ID == ID
                    select customer).FirstOrDefault();
        }

        public void Customer_Update(Customer customer)
        {
            DB.Entry(customer).State = EntityState.Modified;
            DB.SaveChanges();
        }

        public void Customer_Insert(Customer customer)
        {
            DB.Customers.Add(customer);
            DB.SaveChanges();
        }

        public void Customer_Delete(Customer customer)
        {
            DB.Customers.Remove(customer);
            DB.SaveChanges();
        }


    }
}

数据模型//

namespace CustOrderTest.Models
{
    public class Customer
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
    public class CustomerOrder
    {
        public int ID { get; set; }
        public Customer Customer { get; set; }
        public DateTime OrderDate { get; set; }
        public int MyProperty { get; set; }
        public List<CustomerOrderDetail> OrderDetails { get; set; }
    }

    public class CustomerOrderDetail
    {
        public int ID { get; set; }
        public string Part { get; set; }
        public int Quantity { get; set; }
        public double Price { get; set; }

    }

    public class COContext : DbContext
    {
        public DbSet<Customer> Customers { get; set; }
        public DbSet<CustomerOrder> CustomerOrders { get; set; }
        public DbSet<CustomerOrderDetail> OrderDetails { get; set; }
    }

}

    

解决方法

        愚蠢的错误-这就是答案。 如果收到此错误，则很可能是您未指定DataKeyNames

    <asp:GridView ID=\"GridView1\" runat=\"server\" AutoGenerateColumns=\"False\" DataKeyNames=\"ID\" DataSourceID=\"CustomersODS\">