I'm using EntityFramework together with System.Linq.Dynamic and I've defined Employee POCO class as follows:
public class Employee
{
public long Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public Company Company { get; set; }
public Country Country { get; set; }
}
I'm using this code to do a GroupBy the Country Name:
var query = Employees.Include(e => e.Company).Include(e => e.Country);
var groupByQuery = query.GroupBy("new (Country.Code as GroupByField)", "new (it AS XEmployee, it.Company AS XCompany, it.Country AS XCountry)");
var selectQuery = groupByQuery.Select("new (Key.GroupByField, it as Grouping)");
var grouping = selectQuery.Select("it.Grouping") as IQueryable<IGrouping<DynamicClass, DynamicClass>>;
var objects = grouping.First().AsQueryable() as IQueryable<object>;
// This line gives me : ParseException: No property or field 'XEmployee' exists in type 'DynamicClass'
var employees = objects.Select("it.XEmployee");
It's very strange because when I dump all the properties from the DynamicClass, the XEmployee is a valid public property ?
var firstObject = objects.First();
firstObject.GetType().GetProperties().Dump();
Shows
I've created an extension method which gets a property from an object and casts this to the required type.
See this code for the extension method "Select"
public static class DynamicQueryableExtensions
{
public static IEnumerable<TEntity> Select<TEntity>(this IEnumerable<object> source, string propertyName)
{
return source.Select(x => GetPropertyValue<TEntity>(x, propertyName));
}
private static T GetPropertyValue<T>(object self, string propertyName)
{
var type = self.GetType();
var propInfo = type.GetProperty(propertyName);
try
{
return propInfo != null ? (T)propInfo.GetValue(self, null) : default(T);
}
catch
{
return default(T);
}
}
}
The code is used as follows:
// This line will just work fine.
var employees = objects.Select<Employee>("XEmployee");
employees.Dump();
For a working example, see my KendoGridBinderEx project on github.