Lambda Expression Entity Collection

Question

I have an entity collection tied to another entity (navigation property) I will always have one but for some reason it brings it back as a collection. I need to be able to change one property on this object, the DateViewed property.

var test = _personDetail.CurrentPerson.RecentlyViewed;

is there a way to use this new test object in a lambda expression to change the DateViewed property to DateTime.Now

Answer 1

If it is coming back as a collection and it should not be, you need to go into the designer and set the relationship correctly.

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Click on the relationship (the line adjoining the two entities) in the designer, open the properties window, and make sure the End --> Multiplicity property is set to 1 (One) for that end of the relationship.

If it is a "Many-to-one" relationship (ie. the other end of the relationship is set to * (Many) ) , you'll also want to open the Mapping Details (View --> Other Windows --> Mapping Details) and make sure Association --> Maps to... is set to the * Many side of the relationship.

Once this is complete, you should be able to set the DateViewed property like this:

_personDetail.CurrentPerson.DateViewed = DateTime.Now;

Answer 2

Note, I am not 100% certain what you are asking - ie which part comes back as collection, and what RecentlyViewed is (did you mean DateViewed as you mention elsewhere? Taking a guess here - let me know if this isn't what you meant.

If you know there will always be one and only one item in the CurrentPerson collection, you can use Single() - ie:

_personDetail.CurrentPerson.Single().DateViewed = DateTime.Now;