I want to select 2 elements from my database table using LINQ query and I saw an example which use UNION I don't have much experience but I think that maybe this is what I need but I get an error which I can not fix and I'm not sure if it's fixable anyway. So here is my query:
IList<String> materialTypes = ((from tom in context.MaterialTypes
where tom.IsActive == true
select tom.Name)
.Union(from tom in context.MaterialTypes
where tom.IsActive == true
select (tom.ID))).ToList();
Which as it seems is complaining about trying to use UNION on IQueryable with IEnumarebale. I tried to fix that by adding ToString() like this - (tom.ID).ToString which led to cleaning the error underline in Visual-Studio-2010 but in runtime I get:
{"LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression."}
Ty, Leron.
This question is related to
c#
visual-studio-2010
linq
EDIT:
Ok I found why the int.ToString() in LINQtoEF fails, please read this post: Problem with converting int to string in Linq to entities
This works on my side :
List<string> materialTypes = (from u in result.Users
select u.LastName)
.Union(from u in result.Users
select SqlFunctions.StringConvert((double) u.UserId)).ToList();
On yours it should be like this:
IList<String> materialTypes = ((from tom in context.MaterialTypes
where tom.IsActive == true
select tom.Name)
.Union(from tom in context.MaterialTypes
where tom.IsActive == true
select SqlFunctions.StringConvert((double)tom.ID))).ToList();
Thanks, i've learnt something today :)
Source: Stackoverflow.com