Web API + ODataQueryOptions + $top or $skip is causing a SqlException - asp.net-mvc

Question

This code has been simplified for this example.
The query is actually returned from a service, which is why I would prefer to write the method this way.
[HttpGet]
public PageResult<ExceptionLog> Logging(ODataQueryOptions<ExceptionLog> options)
{
var query = from o in _exceptionLoggingService.entities.ExceptionDatas
select new ExceptionLog {
ExceptionDataId = o.ExceptionDataId,
SiteId = o.SiteId,
ExceptionDateTime = o.ExceptionDateTime,
StatusCode = o.StatusCode,
Url = o.Url,
ExceptionType = o.ExceptionType,
ExceptionMessage = o.ExceptionMessage,
Exception = o.Exception,
RequestData = o.RequestData
};
var results = options.ApplyTo(query) as IEnumerable<ExceptionLog>;
var count = results.LongCount();
return new PageResult<ExceptionLog>(results, Request.GetNextPageLink(), count);
}
The above code errors on "results.LongCount()" with the following Exception:
SqlException: The text, ntext, and image data types cannot be compared or sorted, except when using IS NULL or LIKE operator.
It appears that I'm getting an exception with when trying to page, like this "$top=2". Everything works fine if my querystring is like this "$filter=ExceptionDataId gt 100".
Since ExceptionData (the Entity) matches ExceptionLog (business model) I can do something like this as a workaround:
[HttpGet]
public PageResult<ExceptionLog> Logging(ODataQueryOptions<ExceptionData> options)
{
var query = from o in _exceptionLoggingService.entities.ExceptionDatas
orderby o.ExceptionDateTime descending
select o;
var results = from o in options.ApplyTo(query) as IEnumerable<ExceptionData>
select new ExceptionLog {
ExceptionDataId = o.ExceptionDataId,
SiteId = o.SiteId,
ExceptionDateTime = o.ExceptionDateTime,
StatusCode = o.StatusCode,
Url = o.Url,
ExceptionType = o.ExceptionType,
ExceptionMessage = o.ExceptionMessage,
Exception = o.Exception,
RequestData = o.RequestData
};
return new PageResult<ExceptionLog>(results, Request.GetNextPageLink(), results.LongCount());
}
But this doesn't completely work for me because it's a little hackish and I can't use the service's method which already gives me an IQueryable.
Another thing to note, is if the Logging method is converted to IQueryable, everything works correctly. But I need to return the Count with the query so I have to return a PageResult.

Answer 1

This is the workaround I'm using. I only apply the filter from the ODataQueryOptions and I manually apply the Top and Skip.
First I created some extension methods:
using System;
using System.Collections.Generic;
using System.Linq;
namespace System.Web.Http.OData.Query
{
public static class ODataQuerySettingsExtensions
{
public static IEnumerable<T> ApplyFilter<T>(this IQueryable<T> query, ODataQueryOptions<T> options)
{
if (options.Filter == null)
{
return query;
}
return options.Filter.ApplyTo(query, new ODataQuerySettings()) as IEnumerable<T>;
}
public static IEnumerable<T> ApplyTopAndTake<T>(this IEnumerable<T> query, ODataQueryOptions<T> options)
{
IEnumerable<T> value = query;
if (options.Top != null)
{
value = value.Take(options.Top.Value);
}
if (options.Skip != null)
{
value = value.Skip(options.Skip.Value);
}
return value;
}
}
}
Now my method looks like this:
[HttpGet]
public PageResult<ExceptionLog> Logging(ODataQueryOptions<ExceptionLog> options)
{
// GetLogs returns an IQueryable<ExceptionLog> as seen in Question above.
var query = _exceptionLoggingService.GetLogs()
.ApplyFilter(options);
var count = query.Count();
var results = query.ApplyTopAndTake(options);
return new PageResult<ExceptionLog>(results, Request.GetNextPageLink(), count);
}