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  1. PO
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    <p>I don't know how to make it work with data annotations but with Fluent API you can apply and experiment with the trick from here: <a href="http://blog.cincura.net/232731-mapping-private-protected-properties-in-entity-framework-4-x-code-first/" rel="nofollow">http://blog.cincura.net/232731-mapping-private-protected-properties-in-entity-framework-4-x-code-first/</a></p> <p>For your model it would look like the following:</p> <pre><code>public class User { public virtual long Id{get; set;} public virtual ICollection&lt;Tag&gt; Tags { get; protected set; } } public class Tag { public virtual long Id{get; set;} internal protected virtual ICollection&lt;User&gt; Users { get; set; } public class PropertyAccessors { public static readonly Expression&lt;Func&lt;Tag, ICollection&lt;User&gt;&gt;&gt; Users = t =&gt; t.Users; } } </code></pre> <p>Mapping in FluentAPI:</p> <pre><code>modelBuilder.Entity&lt;User&gt;() .HasMany(u =&gt; u.Tags) .WithMany(Tag.PropertyAccessors.Users); </code></pre> <p>This works and creates the expected many-to-many relationship.</p> <p>But I am not sure if you can do anything useful with that navigation property. The fact that you have the property <code>protected</code> and <code>virtual</code> lets me guess that you basically want lazy loading support inside of the entity class or derived classes.</p> <p>The problem is that apparently (according to my tests at least) lazy loading doesn't work for anything else than a <code>public</code> property. The loaded tag is a proxy but the navigation collection is always <code>null</code> (unless the property is <code>public</code>).</p> <p>Moreover, even eager and explicit loading don't work:</p> <p>Outside of the <code>Tag</code> class:</p> <pre><code>// Eager loading var tag = context.Tags.Include(Tag.PropertyAccessors.Users).First(); // Explicit loading var tag2 = context.Tags.First(); context.Entry(tag2).Collection(Tag.PropertyAccessors.Users).Load(); </code></pre> <p>Or inside of the <code>Tag</code> class (some method in <code>Tag</code> which gets the context passed):</p> <pre><code>public DoSomething(MyContext context) { // Eager loading var tag = context.Tags.Include(t =&gt; t.Users).First(); // Explicit loading context.Entry(this).Collection(t =&gt; t.Users).Load(); } </code></pre> <p>In all cases I get an exception that the property <code>Users</code> on entity <code>Tag</code> is not a valid navigation property. (The exception disappears as soon as I make the property <code>public</code>.)</p> <p>I don't know if adding/removing/updating relationships would work. (I doubt.)</p> <p>It looks that you can map a non-public navigation property with this approach to generate the expected database schema. But it seems that there is nothing useful you can do with it.</p>
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    1. POInverseProperty with Database Migration doesn't work when property is protected or internal
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    1. USSlauma
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      1. VTUpMod
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    1. COI want to reach for a solution using DataAnnotation. I didn't yet tried Data Migrations with Fluent APIs and not sure if it will work.
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      1. USMuhammad Soliman
    2. COCode First never maps private or internal members by default. You must use the fluent API to map them, as @Slauma showed. You cannot do this with data annotations. However, once you map the property using the fluent API, then any data annotation on that property will be respected. So, for example, if you added a MaxLength attribute to a private property then it still would not be included in the model. But if you also used the fluent API to map the property, then the MaxLength attribute would be read and used.
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      1. USArthur Vickers
    3. COUsing Fluent API you can map internal properties in Code First. I've tried that and it works for ages now. For protected members you need to do what @Slauma specified above.
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      1. USMuhammad Soliman
 

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