Include collection in Entity Framework Core

Include collection in Entity Framework Core

To include a collection in Entity Framework Core, you can use the Include method to specify the related entities to include in the query results.

Here's an example of how to include a collection in Entity Framework Core:

using Microsoft.EntityFrameworkCore;

// Define your DbContext and entity classes here

using (var context = new MyDbContext())
{
    // Get a queryable for the parent entity and include the child collection
    var query = context.ParentEntities.Include(p => p.ChildEntities);

    // Execute the query and retrieve the results
    var results = query.ToList();

    // Process the results here
}

In the example code, we first create an instance of our DbContext class, MyDbContext.

We then define a query that retrieves all ParentEntity objects from the database and includes the related ChildEntity objects for each parent using the Include method.

We execute the query using the ToList method, which retrieves the results from the database and returns a list of ParentEntity objects with their related ChildEntity objects included.

We can then process the results as needed.

Note that you can also use the ThenInclude method to include additional levels of related entities in the query. For example, if ChildEntity has a related GrandChildEntity collection, you can include both the ChildEntity and GrandChildEntity collections in the query like this:

var query = context.ParentEntities
                   .Include(p => p.ChildEntities)
                       .ThenInclude(c => c.GrandChildEntities);

This will include both the ChildEntity and GrandChildEntity collections for each ParentEntity object in the query results.

Examples

  1. Include collection in Entity Framework Core query

    • Description: Demonstrates how to include a related collection navigation property in an EF Core query using the Include() method.
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities)
    .ToList();

  2. Entity Framework Core include collection with multiple levels

    • Description: Shows how to include a nested collection navigation property in an EF Core query using dot notation.
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities.Select(child => child.GrandChildEntities))
    .ToList();

  3. EF Core include related collection eagerly

    • Description: Eagerly loads the related collection navigation property in an EF Core query to avoid lazy loading.
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities)
    .ToList();

  4. Include collection navigation property in EF Core query dynamically

    • Description: Dynamically includes a related collection navigation property in an EF Core query using a string for the property name.
    var propertyName = "ChildEntities";
var result = dbContext.ParentEntities
    .Include(propertyName)
    .ToList();

  5. EF Core include collection in query with condition

    • Description: Includes a related collection navigation property in an EF Core query based on a condition using ThenInclude().
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities)
        .ThenInclude(child => child.GrandChildEntities.Where(gc => gc.IsActive))
    .ToList();

  6. Include collection in EF Core query from another DbContext

    • Description: Demonstrates how to include a related collection navigation property from another DbContext using the Include() method.
    var result = dbContext1.ParentEntities
    .Include(parent => parent.ChildEntities)
    .ToList();

  7. EF Core include collection navigation property using lambda expression

    • Description: Utilizes lambda expression to include a related collection navigation property in an EF Core query.
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities)
    .ToList();

  8. Entity Framework Core include collection property eagerly with Where condition

    • Description: Eagerly loads the related collection navigation property in an EF Core query based on a condition using Include() and Where().
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities.Where(child => child.IsActive))
    .ToList();

  9. EF Core include collection with ThenInclude for nested properties

    • Description: Includes a related collection navigation property along with its nested properties using ThenInclude() in an EF Core query.
    var result = dbContext.ParentEntities
    .Include(parent => parent.ChildEntities)
        .ThenInclude(child => child.GrandChildEntities)
    .ToList();

  10. Include collection navigation property dynamically in EF Core query

    • Description: Dynamically includes a related collection navigation property in an EF Core query using a lambda expression.
    var propertyName = "ChildEntities";
var result = dbContext.ParentEntities
    .Include(parent => EF.Property<IEnumerable<ChildEntity>>(parent, propertyName))
    .ToList();

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