Entity Framework IGrouping error when selecting data

Question

I have this model

public class Project
{
    [Required]
    public Guid Id { get; set; }
    [MaxLength(512)]
    [Required]
    public string ProjectName { get; set; }        
    public Category Category { get; set; }
    [ForeignKey("Category")]
    public Guid? CategoryId { get; set; }
}

public class Category
{
    [Required]
    public Guid Id { get; set; }
    public string CategoryName { get; set; }
    public ICollection<Project> Projects { get; set; }
}

and this is view model:

public class TipoProyectoViewModel
{      
    public string CategoryName { get; set; }
    public IEnumerable<Project> MProject { get; set; }
}

When I am writing my code to get a list of projects group by category

Category = House
{
   { Id = 1, ProjectName = "my project" }
   { Id = 2, ProjectName = "my project2" }
}

Category = Cars
{
    { Id = 3, ProjectName = "my project3" }
    { Id = 5, ProjectName = "my project5" }
}

This is what I have in my controller:

  var categories = _dbContext.Category
                             .Include(c => c.Projects)
                             .GroupBy(e => e.CategoryName)
                             .Select(e => new TipoProyectoViewModel()
                                              { 
                                                  CategoryName = e.Key, 
                                                  MProject = e.Key.Projects 
                                              });

My problem is that I am getting an error in my select when I write

MProject = e.Key.Projects

String does not contain a definition for Projects and no extension method "projects"accepting a first argument of type string could be found. Are you missing a reference?

what am I doing wrong?

Answer 1

You're accessing e.Key , which is a string key of a grouping. Apparently, it doesn't have a property or a method .Projects .

You can collect the Projects from your grouped items like this

MProject = e.SelectMany(cat => cat.Projects);