I have a method that orders a queryable by a property via reflection, like so:
public static IQueryable<TEntity> OrderBy<TEntity>(this IQueryable<TEntity> source, string orderByProperty, bool desc)
{
string command = desc ? "OrderByDescending" : "OrderBy";
var parts = orderByProperty.Split('.');
var parameter = Expression.Parameter(typeof(TEntity), "p");
Expression body = parameter;
if (parts.Length > 1)
{
for (var i = 0; i < parts.Length - 1; i++)
{
body = Expression.Property(body, parts[i]);
}
}
body = Expression.Property(body, property.Name);
var orderByExpression = Expression.Lambda(body, parameter);
resultExpression = Expression.Call(typeof(Queryable), command,
new Type[] { typeof(TEntity), property.PropertyType },
source.Expression, Expression.Quote(orderByExpression));
return source.Provider.CreateQuery<TEntity>(resultExpression);
}
And it works if I use it for the object's properties or its children's properties, but it doesn't work when a child property is a List.
// Success
db.Users.OrderBy("Name", true)
db.Users.OrderBy("CurrentAddress.City.Name", false)
// Fail
db.Users.OrderBy("PhoneLines.RenewalDate", true)
My model is like so:
public class User {
public string Name { get; set; }
public Address CurrentAddress{ get; set; }
public List<Phone> PhoneLines { get; set; }
}
And I am trying to do something like this work:
db.Users.OrderByDescending(x =>
x.PhoneLines
.OrderByDescending(y => y.RenewalDate)
.Select(y => y.RenewalDate).FirstOrDefault()
);
Right now I am only interested in making this work for first level List children, that is, I am not concerned about a cascading list scenario, just one child in the chain is a list.
Is it possible to achieve this via reflection?
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