LINQ dynamic property in select - asp.net

Question

// Hi everyone
i do this call in Action :
[HttpGet]
public virtual ActionResult JsonGetProvinces(int countryId)
{
//WebSiteContext WbContext = new WebSiteContext();
//UnitOfWork UnitofWork = new UnitOfWork(WbContext);
var provinces =
(
from province in unitofWork.ProvinceRepository.All
where province.CountryId == countryId
select new
{
Id = province.Id,
Name = province.GetType().GetProperty("Name_" + CultureManager.GetCurrentCultureShortName()).GetValue(province)
}
).ToList();
return Json(provinces, JsonRequestBehavior.AllowGet);
}
something is wrong with my query :
var provinces =
(
from province in unitofWork.ProvinceRepository.All
where province.CountryId == countryId
select new
{
Id = province.Id,
Name = province.GetType().GetProperty("Name_" + CultureManager.GetCurrentCultureShortName()).GetValue(province)
}
).ToList();
Particulary,
Name = province.GetType().GetProperty("Name_" + CultureManager.GetCurrentCultureShortName()).GetValue(province)
In BDD, there is Name_fr, Name_en columns
and i'm trying to take one dynamically... Is it possible ?
Of course, i can take both and choose dynamically the column in View but i would to know how do...
Thank you for your help

Answer 1

The short answer is you need to change your code a bit and using expression tree inside. Look at this question

Answer 2

EF can not translate function calls to SQL. Using expression trees can be comlicated see this question
Here is a sample with expression trees. The GetQuery2 is the same as GetQuery but with expression tree and a propertyname parameter.
public static IQueryable<Foo> GetQuery(BlogContext context)
{
var query = from x in context.BlogEntries
select new Foo
{
NameX = x.Name
};
return query;
}
public static IQueryable<Foo> GetQuery2(BlogContext context, string propertyName)
{
ConstructorInfo ci = typeof(Foo).GetConstructor(new Type[0]);
MethodInfo miFooGetName = typeof(Foo).GetMethod("set_NameX");
MethodInfo miBlogEntry = typeof(BlogEntry).GetMethod("get_" + propertyName);
ParameterExpression param = Expression.Parameter(typeof(BlogEntry), "x");
IQueryable<Foo> result = Queryable.Select<BlogEntry, Foo>(
context.BlogEntries,
Expression.Lambda<Func<BlogEntry, Foo>>(
Expression.MemberInit(
Expression.New(ci, new Expression[0]),
new MemberBinding[]{
Expression.Bind(miFooGetName,
Expression.Property(param,
miBlogEntry))}
),
param
)
);
return result;
}
It is easier the fetch all all language strings and write an additional Property Name that does the magic.