我在 Entity Framework 中有一个通用存储库的实现,我正在尝试改进它以使用 EF 提供的 .Include(..) 函数,而不是通过字符串包含导航属性,以便能够安全地重命名属性。
下面是我当前的代码:
public IQueryable<T> GetAll(
Expression<Func<T, bool>> filter = null,
Func<IQueryable<T>, IOrderedQueryable<T>> orderBy = null,
string includeProperties = "")
{
IQueryable<T> 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);
}
else
{
return query;
}
}
我目前通过以下方式使用它:
repository.GetAll(
u => u.Name = "John",
u => u.OrderBy(x => x.Name),
"Address.State",
);
我的问题是:如何更改方法以便能够以下列方式(或类似方式)调用它:
repository.GetAll(
u => u.Name = "John",
u => u.OrderBy(x => x.Name),
u => u.Include(x => x.Address).ThenInclude(x => x.State),
);
最佳答案
我建议您保留两种方法,一种接受字符串参数,一种接受表达式参数。您的存储库的一些客户端可以更好地使用字符串签名,其中一些可以更好地使用表达式签名,这为它们带来了 IntelliSense。
public IQueryable<T> GetAll(params string[] including)
{
var query = dbSet.AsQueryable();
if (including != null)
including.ToList().ForEach(include =>
{
if (!string.IsNullOrEmpty(include))
query = query.Include(include);
});
return query;
}
public IQueryable<T> GetAll(params Expression<Func<T, object>>[] including)
{
var query = dbSet.AsQueryable();
if (including != null)
including.ToList().ForEach(include =>
{
if (include != null)
query = query.Include(include);
});
return query;
}
确保您已添加 using System.Data.Entity;
。
您可以用相同的方式实现过滤和排序的逻辑。对于过滤和排序的字符串参数签名,您可以使用 System.Linq.Dynamic
包。
示例:
var result1 = schoolRepository.GetAll("Students", "Teachers");
var result2 = schoolRepository.GetAll(x=>x.Students, x=>x.Teachers);
关于c# - Entity Framework 通用存储库,包括通过参数的属性,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53965044/