c# - EF 6. Multiple added entities may have the same primary key. Error -

i working on c# project using entity framework 6

i want update-database have error after 'running seed method'

unable determine principal end of 'cookerapi.models.category_recipe_recipe' relationship. multiple added entities may have same primary key. 

here's part of seed method:

            context.recipes.addorupdate(x => x.id_recipe,                 new recipe() { id_recipe = 1, id_user = 1, id_category_main = 1, name_recipe = "zupa z kurek", rate = 0, level = "Łatwe", date_recipe = datetime.now, url_photo = "test", time = 45, number_person = 4, steps = 4, instruction = "test" }                 );               context.categories_recipes.addorupdate(x => x.id_category_recipe,                 new category_recipe() { id_category_recipe = 1, id_recipe = 1, id_category = 1 }                 ); 

category_recipe model:

public class category_recipe {     [key]     [databasegenerated(databasegeneratedoption.identity)]     public int id_category_recipe{ get; set; }      public int id_category { get; set; }      public int id_recipe { get; set;}      [foreignkey("id_category")]     public category category { get; set; }     [foreignkey("id_recipe")]     public recipe recipe { get; set; }  } 

recipe model:

public class recipe     {         [key]         [databasegenerated(databasegeneratedoption.identity)]         public int id_recipe { get; set; }         public int id_user { get; set; }         public int id_category_main { get; set; }          public string name_recipe { get; set; }         public int rate { get; set; } //rate 0-5         public string level { get; set; }         public datetime date_recipe { get; set; } //date of create         public string url_photo { get; set; } //url of thumbnail         public int time { get; set; } // in minutes         public int number_person { get; set; } // recipe number of people         public int steps { get; set; }         public string instruction { get; set; }          [foreignkey("id_user")]         public user user { get;set;}         [foreignkey("id_category_main")]         public category_main category_main { get; set; }          public icollection<category_recipe> categories_recipes { get; set; }         public icollection<comment> comments { get; set; }         public icollection<element> elements { get; set; }         public icollection<rate> rates { get; set; }      } 

where problem , how can fix ?

solution:

context.recipes.addorupdate(x => x.id_recipe,                 new recipe() { id_recipe = 1, id_user = 1, id_category_main = 1, name_recipe = "zupa z kurek", rate = 0, level = "Łatwe", date_recipe = datetime.now, url_photo = "test", time = 45, number_person = 4, steps = 4, instruction = "test" } ); 

replace with:

    context.categories_recipes.add(new category_recipe() { id_recipe = 3, id_category = 3 });     context.savechanges();