ADO.NET Entity framework navigation property trap.

Navigation properties (EntityCollection or EntityReference) of entity object can be automatically loaded without calling their Load method because of they can be already loaded to ObjectStateManager before.

Such behaviour may confuse people how are newbie in using EF and they started use these properties without calling load method before. (You can also use include method of your entity set)

As written in msdn your should first of check if EntityCollection or EntityReference is loaded then if not call the load method.

Also to simplify this process i write some extensions methods which incapsulate this logic:

namespace System.Data.Objects.DataClasses

{

      /// <summary>

      /// Entity extensions

      /// </summary>

      public static class EntityExtensions

      {

            /// <summary>

            /// Ensures that entity referenced by <paramref name="entityReference"/> is loaded.

            /// </summary>

            public static void EnsureLoad<TEntity>(this EntityReference<TEntity> entityReference) where TEntity : EntityObject

            {

                  if (!entityReference.IsLoaded)

                  {

                        entityReference.Load();

                  }

            }

            /// <summary>

            /// Ensures that entity collection is loaded.

            /// </summary>

            public static void EnsureLoad<TEntity>(this EntityCollection<TEntity> entityCollection) where TEntity : EntityObject

            {

                  if (!entityCollection.IsLoaded)

                  {

                        entityCollection.Load();

                  }

            }

      }

}