[Solved] Set initial sort and group settings based on property name

[Josh Anderson]

I'm trying to set the initial sorting of an MVC Grid using property names passed through the Model. Here's how my model looks:

public class RenderViewModel
{
    public RenderViewModel()
    {
        VisibleProperties = new List<string>();
        GroupByProperties = new List<string>();
        Orders = new List<RenderViewOrderByModel>();
    }

    public string Name { get; set; }
    public int Id { get; set; }
    public List<string> VisibleProperties { get; set; }
    public int PageSize { get; set; }
    public List<string> GroupByProperties { get; set; }
    public List<RenderViewOrderByModel> Orders { get; set; }
}

public class RenderViewOrderByModel
{
    public string PropertyName { get; set; }
    public bool Ascending { get; set; }
}

The problem is that I can't figure out how to get the grid initial sorting to work. Here's what I've tried:

<div class="body corners noTR noTL">
    @(Html.Telerik().Grid<ItemsViewModel>()
        .Name("ItemsGrid")
        .Columns(columns =>
        {
            columns.Bound(x => x.Id)
                .Visible(!Model.VisibleProperties.Any() || Model.VisibleProperties.Contains("Id"))
                .Title("Number")
                .Width(50)
                .HeaderHtmlAttributes(new { @style = "text-align: center;" })
                .HtmlAttributes(new { @style = "text-align: center;" });
            columns.Bound(x => x.Name)
                .Visible(!Model.VisibleProperties.Any() || Model.VisibleProperties.Contains("Name"))
                .Title("Name");
        })
        .Groupable(grouping =>
            grouping.Groups(groups =>
                Model.GroupByProperties.ForEach(x =>
                    groups.Add(c => typeof(ItemsViewModel).GetProperty(x)))))
                .DataBinding(db => db.Ajax().Select("RenderItems", "Views", new { id = Model.Id }))
        .Pageable(pager => pager.PageSize(Model.PageSize))
        .Sortable(sorting => sorting.SortMode(GridSortMode.MultipleColumn)
            .OrderBy(ordering =>
                         {
                             Model.Orders.Where(x => x.Ascending).ToList().ForEach(x => ordering.Add(c => c.GetType().GetProperty(x.PropertyName)).Ascending());
                             Model.Orders.Where(x => !x.Ascending).ToList().ForEach(x => ordering.Add(c => c.GetType().GetProperty(x.PropertyName)).Descending());
                         }))
        .ClientEvents(events => events.OnDataBound("grid_onDataBound"))
    )
</div>

You can see I've tried two methods of reflection to get the property instance. In the grouping, I tried retrieving the property by name by a typeof(ItemsViewModel) call. In sorting, I tried using the class instance passed in the lambda expression (c.GetType()). Neither work.

Sorting/grouping after that initial rendering work, so it's not a problem with that core functionality.

Is there any way to set the initial sorting and grouping by using the property name only?

[Josh Anderson]

Looks like in the case of sorting I paid too much attention to the examples and didn't simply look at the method definition. You can add sorting and grouping by string as it is.

.Sortable(sorting => sorting.SortMode(GridSortMode.MultipleColumn)
    .OrderBy(ordering => //ordering.Add(c => c.Id)))
                 {
                     Model.Orders.Where(x => x.Ascending).ToList().ForEach(x => ordering.Add(x.PropertyName));
                     Model.Orders.Where(x => !x.Ascending).ToList().ForEach(x => ordering.Add(x.PropertyName).Descending());
                 }))

However, the grouping doesn't work the same way. Any guidance on how to accomplish this for grouping?

[Josh Anderson]

I'm solving my own problems here...

After looking through the source I added the following method to the GridGroupFactory class definition:

public GridGroupDescriptorBuilder<TModel> Add(string memberName, ListSortDirection sortDirection)
{
    var descriptor = new GroupDescriptor();
    descriptor.Member = memberName;
    descriptor.SortDirection = sortDirection;
    descriptor.MemberType = typeof (TModel).GetProperty(memberName).GetType();

    settings.Groups.Add(descriptor);

    return new GridGroupDescriptorBuilder<TModel>(descriptor);
}

Once I compiled and replaced the Telerik.Web.Mvc.dll in my project, I was able to load initial group settings in this way:

@(Html.Telerik().Grid<ViewModel>()
    .Name("MyGrid")
    .Groupable(grouping =>
        grouping.Groups(groups => Model.GroupByProperties
                                .ForEach(x => groups.Add(x.PropertyName, x.Ascending ? ListSortDirection.Ascending : ListSortDirection.Descending))))
    .DataBinding(db => db.Ajax().Select("RenderGrid", "Views", new { id = Model.Id }))
    .Sortable(sorting => sorting.SortMode(GridSortMode.MultipleColumn)
        .OrderBy(ordering => //ordering.Add(c => c.Id)))
                     {
                         Model.Orders.Where(x => x.Ascending).ToList().ForEach(x => ordering.Add(x.PropertyName));
                         Model.Orders.Where(x => !x.Ascending).ToList().ForEach(x => ordering.Add(x.PropertyName).Descending());
                     }))
)

It would be nice for this to make it into a future version of the controls, but in the meantime if anyone else can benefit from this here you go.

[Rosen]

Hello Josh Anderson,

Thanks for your suggestion. We have added similar overloads to the group descriptor factory, which will be available with the next release of the component.

Regards,
Rosen
the Telerik team