Invoke constructor inside a linq query [duplicate]

问题

This question already has answers here:

Only parameterless constructors and initializers are supported in LINQ to Entities (13 answers)

Closed 6 years ago.

I need to invoke a constructor inside of a linq query.

I am getting this error:

Only parameterless constructors and initializers are supported in LINQ to Entities.

Here's my linq query:

IQueryable<Object> list = (from u in db.Object select new Object(u));

Here is my constructor:

public Object(Object presentation){}

回答1:

You have to use a contructor without parameters.

public Object()
{
    public Object Presentation { get; set; }
}

IQueryable list= (from u in db.Object select new Object { Presentation = u });

回答2:

IQueryable list = db.Object.Select(o => new Object(o))

来源：https://stackoverflow.com/questions/17144884/invoke-constructor-inside-a-linq-query