首先使用Entity框架代码实现Generic Repository [英] Implementing Generic Repository using Entity framework code first

问题描述

我遇到了我的关于实施框架的通用仓库模式和单位的第一次尝试。我不是在手项目中使用MVC。
请看一看这个方法包括在通用仓库等级：

I'm experiencing my first try on implementing Generic Repository Pattern and Unit of framework. I'm not using MVC on the project in hand. Please take a look at this method included in Generic Repository class:

public virtual IEnumerable<TEntity> Get(
        Expression<Func<TEntity, bool>> filter = null,
        Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
        string includeProperties = "")
    {
        IQueryable<TEntity> query = dbSet;

        if (filter != null)
        {
            query = query.Where(filter);
        }

        foreach (var includeProperty in includeProperties.Split
            (new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
        {
            query = query.Include(includeProperty);
        }

        if (orderBy != null)
        {
            return orderBy(query).ToList();
        }
        else
        {
            return query.ToList();
        }
    }

它必须是一个有效的方法，并完成的目标枯井。
我的问题是，我不能为了结果作为降？任何人都可以编写一些代码行，以帮助我在这？谢谢，

it must be a powerful method and accomplishes the goal of DRY well. My problem is that, I cannot order the result as descending? Can anyone write some lines of code to help me on this? Thanks,

推荐答案

要按照产品类别进行筛选，试试这个：

To filter by product category, try this:

var repo = new GenericRepository<Product>();

var results = repo.Get(
    p => p.Category.Name == "Foo");

下面我们声明的通用信息库的一个实例，与产品的实体类型，然后我们通过一个LAMDA表达式执行每个产品的类别名称为富的过滤。

Here we declare an instance of the Generic Repository, with an entity type of Product, then we pass a lamda expression that performs the filtering on each Product's Category whose name is "Foo".

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