无法隐式转换类型&#39;System.Collections.Generic.List <AnonymousType#1> &#39;到&#39;System.Collections.Generic.List

Question

I am new to LINQ I am getting this error

Cannot implicitly convert type System.Collections.Generic.List<AnonymousType#1> to System.Collections.Generic.List<DirCert.Data.Model.DssClient_Sasid_Certified>

I can't figure out how to solve this error.

Here is my code:

public List<DssClient_Sasid_Certified> GetCertifiedRecordsbySasid(string Sasid)
{
    return (from o in _context.DssClient_Sasid_Certified
            where (o.SasId == Sasid)
            join t in _context.DssClients on o.ClientId equals t.ClientId
            select new 
            {
                ClientId = o.ClientId,
                SasId = o.SasId,
                FormalLastName = o.FormalLastName,
                FormalFirstName  = o.FormalFirstName,
                FormalMiddleName = o.FormalMiddleName,
                BenefitSource = t.BenefitSource,
                DOB = o.DOB
            }).ToList();
}

Answer 1

Your select clause:

select new 
{
    ...
}

is selecting an anonymous type. You need it to select a DssClient_Sasid_Certified , so that you can return the type that your method declaration says you're going to return. You may just need to change your code to:

select new DssClient_Sasid_Certified
{
    ...
}

... assuming DssClient_Sasid_Certified has all the properties you're setting, of course.

Answer 2

Your method is supposed to be returning a List of DssClient_Sasid_Certified, but your linq query is creating an anon type.

You could do something like:

public List<DssClient_Sasid_Certified> GetCertifiedRecordsbySasid(string Sasid)
{

    return (from o in _context.DssClient_Sasid_Certified
            where (o.SasId == Sasid)
            join t in _context.DssClients
                     on o.ClientId equals t.ClientId
            select new DssClient_Sasid_Certified()
            {
                ClientId = o.ClientId,
                SasId = o.SasId,
                FormalLastName = o.FormalLastName,
                FormalFirstName  = o.FormalFirstName,
                FormalMiddleName = o.FormalMiddleName,
                BenefitSource = t.BenefitSource,
                DOB = o.DOB
            }).ToList();

}   

This is of course assuming your object has a parameterless constructor for DssClient_Sasid_Certified, and that the properties you're using in your anon object are the same as your DssClient_Sasid_Certified

The line from your original query:

select new .....

Basically says, create me a new Anonymous type, which an anonymous type cannot be converted automagically to a non anonymous type (your list of DssClient_Sasid_Certified).

Read more about Anonymous types here: http://msdn.microsoft.com/en-us/library/bb397696.aspx

Answer 3

Error message states it clearly.Your return type is List<DssClient_Sasid_Certified> but you are trying to return a list of anonymous types.So the types do not match,they are not compatible. You need to create instances of your type instead of anonymous types:

select new DssClient_Sasid_Certified { .. }