Dapper.NET multi mapping TSecond Deserializer is null
I'm trying to perform a very standard multi mapping query using Dapper, and I'm getting the following error. I also get another error occasionally when this seems to work, but I'm unable to reproduce it at the moment. I'll append it to this post if/when the first problem is solved.
Here is the query code:
const string storedProc = "dbo.GetStopsForRouteID";
var stops = conn.Query<RouteStop, MapLocation, RouteStop>(
storedProc, (stop, loc) =>
{
stop.Location = loc;
return stop;
}, new { RouteID = routeId }, commandType: CommandType.StoredProcedure);
In Dapper.cs on line 498:
var deserializer2 = (Func<IDataReader, TSecond>)info.OtherDeserializers[0];
info.OtherDeserializers is null which causes a NullReferenceException.
This is the guts of the stored procedure:
SELECT
RouteStops.StopID,
RouteStops.Name,
RouteStops.Description,
RouteStops.IsInbound,
RouteStops.Location.Lat as Latitude,
RouteStops.Location.Long as Longitude
FROM dbo.Routes
I开发者_运维技巧NNER JOIN dbo.StopsOnRoute ON
Routes.RouteID = StopsOnRoute.RouteID
INNER JOIN dbo.RouteStops ON
StopsOnRoute.StopID = RouteStops.StopID
WHERE Routes.RouteID = @RouteID
ORDER BY StopsOnRoute.SequenceNumber
I've had an extensive look at the dapper code but I can't find anything that seems out of place other than that TFirst's deserialiser isn't null, but TSecond's is. Could there be a problem when it creates TSecond's deserializer that leaves it as null?
Here are the types:
public class MapLocation
{
public double Latitude { get; set; }
public double Longitude { get; set; }
}
public class RouteStop {
public int StopID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool IsInbound { get; set; }
public MapLocation Location { get; set; }
}
Probably the main problem here is that you haven't told it how to "split"; try adding the parameter:
splitOn: "Latitude"
without that, as far as dapper can see there is no second result portion (it splits on Id
by default).
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