目前项目中使用到的EntityFramework中几种操作小结，先标记下。没有详细介绍，后续有空的话再补充一些并完善一下。
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列中加入RowVersion时间戳
????public
class
Product
????{
????????public
int Id { get; set; }
????????public
string Name { get; set; }
????????[Timestamp]
????????public
Byte[] RowVersion { get; set; }
????}
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查询中加入RowVersion比较
- 编写扩展函数
????internal
static
class
EntityFrameworkHelper
????{
????????public
static
int Compare(this
byte[] b1, byte[] b2)
????????{
????????????throw
new
NotImplementedException("This is only for linq to sql");
????????}
????}
- 用扩展函数查询
????db.Products.Where(i => i.RowVersion.Compare(version) > 0).ToList();
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乐观锁
????public
class
Product
????{
????????public
int Id { get; set; }
????????public
string Name { get; set; }
????????[Timestamp, ConcurrencyCheck]
????????public
Byte[] RowVersion { get; set; }
????}
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带过滤条件的DBSet
- 添加Can a DbContext enforce a filter policy?一文中的FilteredDbSet，
- 修改DbContext，使用FilteredDbSet替换默认的DbSet
????public
IDbSet<Product> Products { get { return
new
FilteredDbSet<Product>(this, i=>i.IsRemoved == false); } }
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标记删除
继承FilteredDbSet，重载其删除函数
????public
interface
IflagRemoveObject
????{
????????bool IsRemoved { get; set; }
????}
????class
FlagRemoveDbSet<T> : FilteredDbSet<T> where
T : class, IflagRemoveObject
????{
????????public
override
T Remove(T entity)
????????{
????????????entity.IsRemoved = true;
????????????return entity;
????????}
????}
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单元测试：
- 打桩DbSet：FakeDbSet
- DbContext的封装