Linq to entities get procedure in new statement - linq

Question

I try to use something like this in a WCF Service:
I have a Table with an offer with Latitude and Longitude. And the Position from the User. In the Query I need the Distance from the user to the offer, and order to this.
private double Distanze(double LAT1, double LON1, double LAT2, double LON2)
{
double e = (3.1415926538 * LAT1 / 180);
double f = (3.1415926538 * LON1 / 180);
double g = (3.1415926538 * LAT2 / 180);
double h = (3.1415926538 * LON2 / 180);
double i = (Math.Cos(e) * Math.Cos(g) *
Math.Cos(f) * Math.Cos(h) + Math.Cos(e) *
Math.Sin(f) * Math.Cos(g) * Math.Sin(h) +
Math.Sin(e) * Math.Sin(g));
double j = (Math.Acos(i));
double k = (6371 * j);
return k;
}
and in the query:
public IQueryable<V1_Off_Offert> Get_myOffert()
{
var User = GetCurrentPers_ID();
if (User != 0)
{
double lat = GetCurrentPOS().LAT;
double lon = GetCurrentPOS().LON;
var query = from c in this.ObjectContext.C1_OFF_OFFERT
where c.C1_PERS_PERSON_ID == User
select new V1_Off_Offert()
{
ID = c.ID,
//......
LAT = (double)c.C1_ORT_GEO.LAT,
LON = (double)c.C1_ORT_GEO.LON,
//This it dosnt Work
Distanz = (double)Distanze((double)c.C1_ORT_GEO.LAT, (double)c.C1_ORT_GEO.LON, lat, lon),
Radius = (double)c.DISTANZ
};
return query;
}
else return null;
}
Is there a way to realize this?

Answer 1

Okay, I see what the problem is. LINQ to SQL is trying to translate Distanze to SQL. It can't, so it dies. You need to do the projection after you've already executed the query on the database.

Answer 2

I Try this:
public IQueryable<V1_Off_Offert> Get_myOffert()
{
var User = GetCurrentPers_ID();
if (User != 0)
{
double lat = GetCurrentPOS().LAT;
double lon = GetCurrentPOS().LON;
var query = from c in this.ObjectContext.C1_OFF_OFFERT
where c.C1_PERS_PERSON_ID == User
select new V1_Off_Offert()
{
ID = c.ID,
Image = c.Image,
Start_Datum = c.VON,
End_Datum = c.BIS,
Name = c.C1_KEY_WORT.WORT,
Text = c.TEXT,
Preis = (decimal)c.PREIS != 0 ? (decimal)c.PREIS : 0,
WORT = c.C1_GRUP_GRUPPE.C1_KEY_WORT.WORT,
PERS_ID = (int)c.C1_PERS_PERSON_ID,
//COM_ID = (int)c.C1_COM_COMP_ID,
EH_ID = c.C1_OFF_EINHEIT_ID,
LAT = (double)c.C1_ORT_GEO.LAT,
LON = (double)c.C1_ORT_GEO.LON,
//Distanz = (double)Distanze((double)c.C1_ORT_GEO.LAT, (double)c.C1_ORT_GEO.LON, lat, lon),
Radius = (double)c.DISTANZ
//LAT = c.C1_ORT_GEO.LAT != null ? (double)c.C1_ORT_GEO.LAT : 0
};
foreach (V1_Off_Offert T in query)
{
T.Distanz = Distanze(T.LAT, T.LON, lat, lon);
}
return query;
}
else return null;
}
this Works:
foreach (V1_Off_Offert T in query)
{
T.Distanz = Distanze(T.LAT, T.LON, lat, lon);
}
Is there a way to use the first Way
maybe as lambda expression.
but it is not so elegant to put the Result of the foreach in to the query!!!