Question

I’m working on a project where I’m trying to use entity framework to provide data to a WCF service. The code follows:

public IQueryable<vwTP90Web> GetTP90()
    {
            TP90Entities context = new TP90Entities();
            var tp90web = (from p
                          in context.vw_TP90Web
                          select p).Cast<IQueryable<vwTP90Web>>();
            return tp90web;

    }

it works fine until I try to return the data and then I get the message:

Cannot implicitly convert type        
'System.Linq.IQueryable<System.Linq.IQueryable<TP90Service.vwTP90Web>>' to 
'System.Linq.IQueryable<TP90Service.vwTP90Web>'. An explicit conversion exists (are   
 you missing a cast?)

I’ve been chasing this for days and I just can’t wrap my head around what it’s looking for. I had the service running when I returned one item,but for the project I need to return a list. Can someone explain to me what I’m doing wrong?

Answer 1

You don’t need to include the IQueryable<T> in your cast:

       var tp90web = (from p
                      in context.vw_TP90Web
                      select p).Cast<vwTP90Web>();

Note that this will still fail at runtime if the query is not returning vwTP90Web instances.