System.NotSupportedException: The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'

[ehsan sadeghi]

@model System.Collections.IEnumerable

 

  

 

@(Html.Kendo().Grid<HoghoughModel.PTStbKarkonan>()

    .Name("Grid")

    .EnableCustomBinding(true)

    .BindTo(Model)

    .Columns(columns => {

        columns.Bound(o => o.IssuePlace);

        columns.Bound(o => o.BimehName);

        columns.Bound(o => o.Family);

        columns.Bound(o => o.Name);

    })

    .Pageable()

    .Sortable()

    .Filterable()

    .Scrollable()

    .Groupable()

    .DataSource(dataSource => dataSource.Server().Total((int)ViewData["total"]))

)

and this code for populating grid :

    public ActionResult Index([DataSourceRequest(Prefix = "Grid")] DataSourceRequest request)

    {

        if (request.PageSize == 0)

        {

            request.PageSize = 10;

        }

 

        IQueryable<PTStbKarkonan> karkonan = db.PTStbKarkonans;

 

        karkonan = karkonan.ApplyFiltering(request.Filters);

 

        var total = karkonan.Count();

 

        karkonan = karkonan.ApplySorting(request.Groups, request.Sorts);

 

        karkonan = karkonan.ApplyPaging(request.Page, request.PageSize);

 

        IEnumerable data = karkonan.ApplyGrouping(request.Groups);

 

        ViewData["total"] = total;

 

        return View(data);

    }

 

public static class PTStbKarkonanExtensions

{

    public static IQueryable<PTStbKarkonan> ApplyPaging(this IQueryable<PTStbKarkonan> data, int page, int pageSize)

    {

        if (pageSize > 0 && page > 0)

        {

            data = data.Skip((page - 1) * pageSize);

        }

 

        data = data.Take(pageSize);

 

        return data;

    }

 

    public static IEnumerable ApplyGrouping(this IQueryable<PTStbKarkonan> data, IList<GroupDescriptor>

        groupDescriptors)

    {

        if (groupDescriptors != null && groupDescriptors.Any())

        {

            Func<IEnumerable<PTStbKarkonan>, IEnumerable<AggregateFunctionsGroup>> selector = null;

            foreach (var group in groupDescriptors.Reverse())

            {

                if (selector == null)

                {

                    if (group.Member == "IssuePlace")

                    {

                        selector = Orders => BuildInnerGroup(Orders, o => o.IssuePlace);

                    }

                    else if (group.Member == "BimehName")

                    {

                        selector = Orders => BuildInnerGroup(Orders, o => o.BimehName);

                    }

                    else if (group.Member == "Family")

                    {

                        selector = Orders => BuildInnerGroup(Orders, o => o.Family);

                    }

                    else if (group.Member == "Name")

                    {

                        selector = Orders => BuildInnerGroup(Orders, o => o.Name);

                    }

                }

                else

                {

                    if (group.Member == "IssuePlace")

                    {

                        selector = BuildGroup(o => o.IDSeri, selector);

                    }

                    else if (group.Member == "BimehName")

                    {

                        selector = BuildGroup(o => o.BimehName, selector);

                    }

                    else if (group.Member == "Family")

                    {

                        selector = BuildGroup(o => o.Family, selector);

                    }

                    else if (group.Member == "Name")

                    {

                        selector = BuildGroup(o => o.Name, selector);

                    }

                }

            }

 

            return selector.Invoke(data).ToList();

        }

 

        return data;

    }

 

    private static Func<IEnumerable<PTStbKarkonan>, IEnumerable<AggregateFunctionsGroup>>

        BuildGroup<T>(Expression<Func<PTStbKarkonan, T>> groupSelector, Func<IEnumerable<PTStbKarkonan>,

        IEnumerable<AggregateFunctionsGroup>> selectorBuilder)

    {

        var tempSelector = selectorBuilder;

        return g => g.GroupBy(groupSelector.Compile())

                     .Select(c => new AggregateFunctionsGroup

                     {

                         Key = c.Key,

                         HasSubgroups = true,

                         Member = groupSelector.MemberWithoutInstance(),

                         Items = tempSelector.Invoke(c).ToList()

                     });

    }

 

    private static IEnumerable<AggregateFunctionsGroup> BuildInnerGroup<T>(IEnumerable<PTStbKarkonan>

        group, Expression<Func<PTStbKarkonan, T>> groupSelector)

    {

        return group.GroupBy(groupSelector.Compile())

                .Select(i => new AggregateFunctionsGroup

                {

                    Key = i.Key,

                    Member = groupSelector.MemberWithoutInstance(),

                    Items = i.ToList()

                });

    }

    public static IQueryable<PTStbKarkonan> ApplySorting(this IQueryable<PTStbKarkonan> data,

                IList<GroupDescriptor> groupDescriptors, IList<SortDescriptor> sortDescriptors)

    {

        if (groupDescriptors != null && groupDescriptors.Any())

        {

            foreach (var groupDescriptor in groupDescriptors.Reverse())

            {

                data = AddSortExpression(data, groupDescriptor.SortDirection, groupDescriptor.Member);

            }

        }

 

        if (sortDescriptors != null && sortDescriptors.Any())

        {

            foreach (SortDescriptor sortDescriptor in sortDescriptors)

            {

                data = AddSortExpression(data, sortDescriptor.SortDirection, sortDescriptor.Member);

            }

        }

 

        return data;

    }

 

    private static IQueryable<PTStbKarkonan> AddSortExpression(IQueryable<PTStbKarkonan> data, ListSortDirection

                sortDirection, string memberName)

    {

        if (sortDirection == ListSortDirection.Ascending)

        {

            switch (memberName)

            {

                case "IssuePlace":

                    data = data.OrderBy(order => order.IssuePlace);

                    break;

                case "BimehName":

                    data = data.OrderBy(order => order.BimehName);

                    break;

                case "Family":

                    data = data.OrderBy(order => order.Family);

                    break;

                case "Name":

                    data = data.OrderBy(order => order.Name);

                    break;

            }

        }

        else

        {

            switch (memberName)

            {

                case "IssuePlace":

                    data = data.OrderByDescending(order => order.IssuePlace);

                    break;

                case "BimehName":

                    data = data.OrderByDescending(order => order.BimehName);

                    break;

                case "Family":

                    data = data.OrderByDescending(order => order.Family);

                    break;

                case "Name":

                    data = data.OrderByDescending(order => order.Name);

                    break;

            }

        }

        return data;

    }

 

    public static IQueryable<PTStbKarkonan> ApplyFiltering(this IQueryable<PTStbKarkonan> data,

        IList<IFilterDescriptor> filterDescriptors)

    {

        if (filterDescriptors != null && filterDescriptors.Any())

        {

            data = data.Where(ExpressionBuilder.Expression<PTStbKarkonan>(filterDescriptors));

        }

        return data;

    }

}

I use EntityFramework. When I run project I get 
System.NotSupportedException: The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'

[ehsan sadeghi]

I Solved this by order befor assign to grid.

[Atanas Korchev]

Hi,

 This is a well known issue of Entity Framework. It requires OrderBy to be called before Skip (as the exception message suggests). Here is a possible solution.

Regards,
Atanas Korchev
the Telerik team