Question

Is it somehow possible to use the ‘With’ keyword on an existing object?

I would like to do the following using LINQ to objects and can’t seem to find a way:

From m as Product in Me _
  Select m With {.Match = m.Name.IndexOf(query)} _ 
  Where m.Name.IndexOf(query) > 0

Answer 1

No there is no way of doing this (With can only be used with a constructor). It would violate the functional principles on which linq is built, specifically that there will not be side-effects.

Best bet is to create a new Product in your select with the Match property set.

From m as Product in Me _
Where m.Name.IndexOf(query) > 0 _
Select New Product() With _
              { _
                  .Match = m.Name.IndexOf(query), _
                  ...apply the rest of m's properties _
              }