Iqueryable anonymous type assign to specific type

Question

Dear All

Thank you for your attention.

My task is to query result using an input field, when the input field is not null, then join another table and get it filtered.

If no input field is entered, just get whole summary.

My works are here

IQueryable<Summary> query = context.Summaries;

if (inputField != null)

{

       var tempQuery = query.Join(context.Others.Where(o=>o.field == inputField),

	 a => a.ID,
         b => b.SummaryID,
        (a, b) => new
                            {
                                a
                            }); 


      query = tempQuery;   <-- Here got a problem

}

tempQuery is IQueryable<AnonymousType> but query is IQueryable<Summary>. cannot compile  here

query = (IQueryable<Summary>)tempQuery;  explict casting is aslo not working

How could I enhance he above program? thanks

---

Best Regards
mintssoul

Answer 1

tempQuery is IQueryable<AnonymousType> but query is IQueryable<Summary>. cannot compile  here

It's telling you it can't make the cast. You have an object car,  and you are telling car  you are going to make it a horse.  Both objects may provide transportation, but they are two different objects.

Also, Summary is a concrete class, and it can't be casted over to an AnonymousType object.

https://msdn.microsoft.com/en-us/library/bb397696.aspx?f=255&MSPPError=-2147217396

Answer 2

tempQuery is IQueryable<AnonymousType> but query is IQueryable<Summary>. cannot compile  here

It's telling you it can't make the cast. You have an object car,  and you are telling car  you are going to make it a horse.  Both objects may provide transportation, but they are two different objects.

Also, Summary is a concrete class, and it can't be casted over to an AnonymousType object.

https://msdn.microsoft.com/en-us/library/bb397696.aspx?f=255&MSPPError=-2147217396

Dear DA924

Thank you for your reply.  The concept IQueryable<AnonymousType> could not convert back to IQueryable<Summary>  is good.

I am now using DTO for manipulating the intermediate result, thanks.

---

Best Regards
mintssoul

Answer 3

tempQuery is IQueryable<AnonymousType> but query is IQueryable<Summary>. cannot compile  here

It's telling you it can't make the cast. You have an object car,  and you are telling car  you are going to make it a horse.  Both objects may provide transportation, but they are two different objects.

Also, Summary is a concrete class, and it can't be casted over to an AnonymousType object.

https://msdn.microsoft.com/en-us/library/bb397696.aspx?f=255&MSPPError=-2147217396

Dear DA924

Thank you for your reply.  The concept IQueryable<AnonymousType> could not convert back to IQueryable<Summary>  is good.

I am now using DTO for manipulating the intermediate result, thanks.

---

Best Regards
mintssoul

A DTO is a concrete class. :)