DataSourceRequest Manipulating / Out of box filtering (FilterDescriptor vs CompositeFilterDescriptor)

[Kerem]

Hi everyone,

I'm working on a grid that needs different type of filtering. For example: I've an hierarchical departments table and when i choose a parent department, grid should show me all students under the children departments. I've spent hours on this and figured it out.

Extension Method:

public static class Extensions
{
    public static List<FilterDescriptor> ToFilterDescriptor(this IList<IFilterDescriptor> filters)
    {
        var result = new List<FilterDescriptor>();
        if (filters.Any())
        {
            foreach (var filter in filters)
            {
                var descriptor = filter as FilterDescriptor;
                if (descriptor != null)
                {
                    result.Add(descriptor);
                }
                else
                {
                    var compositeFilterDescriptor= filter as CompositeFilterDescriptor;
                    if (compositeFilterDescriptor!= null)
                    {
                        result.AddRange(compositeFilterDescriptor.FilterDescriptors.ToFilterDescriptor());
                    }
                }
            }
        }
        return result;
    }
}

In Use:

public ActionResult List([DataSourceRequest] DataSourceRequest request)
{
    var departments= new List<int?>();
    var nRequest = new DataSourceRequest
    {
        Groups = request.Groups,
        Aggregates = request.Aggregates,
        Page = request.Page,
        PageSize = request.PageSize,
        Sorts = request.Sorts,
        Filters = new List<IFilterDescriptor>()
    };

    if (request.Filters.Any())
    {
        foreach (var fdc in request.Filters.ToFilterDescriptor())
        {
            switch (fdc.Member)
            {
                case "DepartmentId":
                    var department = Convert.ToInt32(fdc.Value);
                    departments.AddRange(db.StoredProcedureToTakeDepartmentsTree(department).Select(o => o.Id));
                    break;
               default:
                    nRequest.Filters.Add(new FilterDescriptor
                    {
                        Member = fdc.Member,
                        MemberType = fdc.MemberType,
                        Operator = fdc.Operator,
                        Value = fdc.Value
                    });
                    break;
            }

        }
    }
    if (!departments.Any())
    {
         //departments = default departments if it's empty
    }

    var model = db.Students.Where(o => departments.Contains(o.DepartmentId))
              .Select(o => new
               {
                    o.Id
                   //Some columns
               })
    return Json(model.ToDataSourceResult(nRequest), JsonRequestBehavior.AllowGet);
}

I hope it helps...
Best Regards

[Cornel]

Thanks Kerem for this post, it helped me a lot!

[Reinier]

Hi Kerem,

I use your solution to remove one filter out of the request.filters, but then the structure of the nRequest.filters are changed.

The CompositeFilterDescriptor is removed and there is only a list left of FilterDescriptors.

ToDataSourceResult(nRequest) accept this but what is the effect of this filters for the result?

 

Regards, Reinier Pechler

 

 

[DPA]

Is there a way to remove specific Filter?

[Alex Hajigeorgieva]

Hello, Reinier,

We have a how-to article which shows how to loop and modify filters on the server without changing their type in the documentation here:

https://docs.telerik.com/aspnet-mvc/helpers/grid/how-to/Filtering/get-all-filters-recursively-modify-servre-side

For your convenience, here is the method:

private void ModifyFilters(IEnumerable<IFilterDescriptor> filters)
{
    if (filters.Any())
    {
        foreach (var filter in filters)
        {
            var descriptor = filter as FilterDescriptor;
            if (descriptor != null && descriptor.Member == "OrderDate")
            {
                descriptor.Member = "OrderDate.Date";
            }
            else if (filter is CompositeFilterDescriptor)
            {
                ModifyFilters(((CompositeFilterDescriptor)filter).FilterDescriptors);
            }
        }
    }
}

public ActionResult Read([DataSourceRequest] DataSourceRequest request)
{
    ModifyFilters(request.Filters);

    return Json(OrderRepository.GetAll().ToDataSourceResult(request));
}

I hope this helps.

Kind Regards,
Alex Hajigeorgieva
Progress Telerik

[John]

Hi Alex,

Are there any examples of getting this to work with other Data Types?  Specifically, when I try to do this with int and decimal data types I get the following error:

'Method 'System.String ToLower()' declared on type 'System.String' cannot be called with instance of type 'System.Decimal'.

Thank you,
John

[Tsvetomir]

Hi John,

The example provided by my colleague intends to modify the filter's member value without changing the data type by no means. Could you share an example in which the implementation you are currently working on is present? I will investigate it locally and get back to you with the respective suggestions.

 

Kind regards,
Tsvetomir
Progress Telerik