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Setting dynamic sort name in linq query

I want to get a query OrderBythat works with a lambda expression to get an SQL query with the keyword TOP (n) (performance increase).

I can do this if I indicate ...

PaginatedList = query.OrderBy(x => x.QuoteID).Skip(() => skipValue).Take(() => pageSize)

But since I want the orderBy field to be dynamic by selecting a user interface, I want to do something like this:

var propertyInfo = typeof(Data.Quote).GetProperty(sortName);
Expression<Func<Data.Quote, object>> orderField = x => propertyInfo.GetValue(x, null);
PaginatedList = query.OrderBy(orderField).Skip(() => skipValue).Take(() => pageSize)

This gives me an error:

"LINQ to Entities does not recognize the method 'System.Object GetValue (System.Object)', and this method cannot be translated into a storage expression."

I tried this, but not the type Expression<Func<T, object>>

var propertyInfo = typeof(Data.Quote).GetProperty(sortName);
Func<Data.Quote, object> orderField = x => propertyInfo.GetValue(x, null);
PaginatedList = query.OrderBy(x => orderField).Skip(() => skipValue).Take(() => pageSize)

And I get this error:

"It is not possible to create a constant value of type [...]. Only primitive types or enumerations in this context"

, , , .

+2
3

, :

var propertyInfo = typeof(Data.Quote).GetProperty(sortName);

ParameterExpression parameter = Expression.Parameter(typeof(T), "s");
MemberExpression property = Expression.Property(parameter, propertyInfo);
LambdaExpression sort = Expression.Lambda(property, parameter);

MethodCallExpression call = Expression.Call(
                                         typeof(Queryable),
                                         "OrderBy",
                                         new[] {typeof(T), property.Type},
                                         Query.Expression,
                                         Expression.Quote(sort));

var orderedQuery = (IOrderedQueryable<T>)Query.Provider.CreateQuery<T>(call);

PaginatedList = orderedQuery.Skip(skipValue).Take(pageSize);
+3

, . source:

public static class Utility
{
    //makes expression for specific prop
    public static Expression<Func<TSource, object>> GetExpression<TSource>(string propertyName)
    {
        var param = Expression.Parameter(typeof(TSource), "x");
        Expression conversion = Expression.Convert(Expression.Property
        (param, propertyName), typeof(object));   //important to use the Expression.Convert
        return Expression.Lambda<Func<TSource, object>>(conversion, param);
    }


    public static IOrderedQueryable<TSource> 
    OrderBy<TSource>(this IQueryable<TSource> source, string propertyName)
    {
        return source.OrderBy(GetExpression<TSource>(propertyName));
    }
}

, :

var result=Query.OrderBy(sortName)...;
+2

, propertyInfo, , , GetProperty(). var, .

GetValue , GetValue .

+1

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