How Can I Include Nested Properties in Entity Framework Using Include()?

Entity Framework contains nested property levels

When using the Include() method in Entity Framework to retrieve objects containing related data, a common limitation is the lack of support for including multiple levels of nested properties. For example, suppose you have a model where ApplicationServers holds an ApplicationsWithOverrideGroup collection, which in turn contains Application and CustomVariableGroup properties.

Initial attempt:

In order to include nested attributes, you can try the following:

<code class="language-csharp">public IEnumerable<applicationserver> GetAll()
{
    return this.Database.ApplicationServers
        .Include(x => x.ApplicationsWithOverrideGroup)               
        .Include(x => x.ApplicationWithGroupToForceInstallList)
        .Include(x => x.CustomVariableGroups)                
        .ToList();
}</code>

However, this approach will only populate the Enabled property of ApplicationWithOverrideVariableGroup, not the Application or CustomVariableGroup properties.

Solution for EF 6:

To include nested properties in EF 6, use the overload of Include() that accepts a lambda expression:

<code class="language-csharp">using System.Data.Entity;

query.Include(x => x.Collection.Select(y => y.Property));</code>

EF Core’s solution:

In EF Core, use the ThenInclude method to include nested properties:

<code class="language-csharp">using Microsoft.EntityFrameworkCore;

query.Include(x => x.Collection)
     .ThenInclude(x => x.Property);</code>

By using these methods, you can eagerly load nested property levels in Entity Framework, ensuring that your objects are fully populated with necessary data.

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