Entity Framework Core include filter

asp.net-core c# entity-framework-core

Question

I'm new to C# and Entity Framework Core. I have searched a lot for this question but did not found an answer. I have the following three models (I have simplified it):

public class Exercise
{
    public int ExerciseId { get; set; }

    [Required]
    public string ExerciseName { get; set; }

    public string Filename { get; set; }

    public ICollection<ExerciseClinicalPicture> ExerciseClinicalPicture { get; set; }
}

public class ClinicalPicture
{
    [Key]
    public int ClinicalPictureId { get; set; }

    [Required]
    [Display(Name = "Krankheitsbild")]
    public string ClinicalPictureName { get; set; }

    public ICollection<ExerciseClinicalPicture> ExerciseClinicalPicture { get; set; }
}

public class ExerciseClinicalPicture
{
    [Key]
    public int ExerciseClinicalPictureId { get; set; }

    public int ExerciseId { get; set; }

    public Exercise Exercise { get; set; }

    public int ClinicalPictureId { get; set; }

    public ClinicalPicture ClinicalPicture { get; set; }
}

Now I want to have a query where the result is a collection of all exercises which are associated with a certain clinical picture and the clinicalPicture is included.

Something like this:

int id = 1;
exercises = _context.Exercise.Where(e => e.ExerciseClinicalPicture.ClinicalPictureId == id)
.Include(m => m.ExerciseClinicalPicture)
.ThenInclude(m => m.ClinicalPicture);

This query throws an error because I can not call ClinicalPictureId on a collection of ExerciseClinicalPicture.

Hope my question is OK like this. It is the first time I ask a question on Stackoverflow.

Thanks a lot for your help

1
0
12/9/2016 5:00:04 PM

Accepted Answer

Change this:

exercises = _context.Exercise.Where(e => e.ExerciseClinicalPicture.ClinicalPictureId == id)

to this:

exercises = _context.Exercise.Where(e => e.ExerciseClinicalPicture.Any(ec => ec.ExerciseId == id))

Basically, "Get exercises where any of the exercise clinical pictures on the exercise contains the given exercise ID." In your models, ExerciseClinicalPicture is a collection. You have to dig into it once more. Your error is that the property doesn't exist because it's a collection.

And this is how you'd query it. Then you can just do your includes as you would normally.

2
12/9/2016 4:19:05 PM


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