我使用部分类扩展实体类.我使用部分类,因此实体的签名不会更改(请参阅Delete方法中的DeleteOnSubmit调用).

我已经做了一个小例子.这是数据库和LINQ to sql类设置的映像：

这里是实现业务逻辑的部分类：

/// <summary>
/// This class extends BusinessLogicDataContext.Products entity class
/// </summary>
public partial class Product
{
    /// <summary>
    /// New up a product by column: dbo.Products.ProductId in database
    /// </summary>
    public Product(Int32 id)
    {
        var dc = new BusinessLogicDataContext();

        // query database for the product
        var query = (
            from p in dc.Products 
            where p.ProductId == id 
            select p
        ).FirstOrDefault();

        // if database-entry does not exist in database,exit
        if (query == null) return;

        /* if product exists,populate self (this._ProductId and
           this._ProductName are both auto-generated private
           variables of the entity class which corresponds to the
           auto-generated public properties: ProductId and ProductName) */
        this._ProductId = query.ProductId;
        this._ProductName = query.ProductName;
    }


    /// <summary>
    /// Delete product
    /// </summary>
    public void Delete()
    {
        // if self is not poulated,exit
        if (this._ProductId == 0) return;

        var dc = new BusinessLogicDataContext();

        // delete entry in database
        dc.Products.DeleteOnSubmit(this);
        dc.SubmitChanges();

        // reset self (you could implement IDisposable here)
        this._ProductId = 0;
        this._ProductName = "";
    }
}

使用实现的业务逻辑：

// new up a product
var p = new Product(1); // p.ProductId: 1,p.ProductName: "A car"

// delete the product
p.Delete(); // p.ProductId: 0,p.ProductName: ""

此外：LINQ to sql实体类本质上是非常开放的.这意味着对应于dbo.Products.ProductId列的属性同时实现了一个getter和一个setter – 这个字段不应该是可以改变的.

据我所知,您不能使用部分类来覆盖属性,所以我通常所做的是实现一个使用接口缩小对象的管理器：

public interface IProduct
{
    Int32 ProductId { get; }

    void Delete();
}