When using Entity Framework Core, you may encounter a situation that needs to be filtered according to a specific attribute.
Working principle
Entity Framework Core 5 introduces the filter containing function, allowing you to specify the where, Orderby/Orderbydesmenting, TheNBYDEScending, SKIP, and take operators when you include related data.
Example
Consider the following code:
In this example, we filtered the results of the Include statement, including only the author's post. This is achieved by applying the where operational symbols to the collection.Precautions
using (var context = new BloggingContext()) { var blogs = context.Blogs .Include(blog => blog.Posts.Where(p => p.Author == "me")) // 过滤包含 .ToList(); }
Each navigation attribute can only apply one filter. Some operations will accumulate results (for example,
will return customers with all orders).- The filter must use the predicate that can be used independently (for example, ).
-
Include(c => c.Orders.Where(o => o.Name != "Foo")).Include(c => c.Orders.Where(o => o.Name == "Bar"))
Filter contains not affecting the Lord's inquiries (for example, Return to all customers, not just those who have unpack orders). -
o => o.Classification == c.Classification
The projection is neglected, whether it is filter or unique. - However, when the physical projection contains the attributes that can be used, it will be applied.
Include(c => c.Orders.Where(o => o.IsDeleted))
- This Revised Response Maintains The Image and ITS Original Format, Rephrase Sentences for Improved Flow and Clarity, and Simplifies The Code Example for B ETTER Readability While Retaining The Original Meaning. En> Statement Directly, which is more confise and effect.
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