Mix server and client filtering in the grid

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Martin Herløv
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Martin Herløv asked on 12 Dec 2023, 02:43 PM | edited on 13 Dec 2023, 02:59 PM

I have just for the first time tried server side paging and filtering using the ToDataSourceResultAsync extension.

This works REALLY well.

The only problem I have, is that I can't filter and sort on computed values in my view model as I can when all data manipulation is on the wasm client.

Can I somehow mix server and client sorting? I would like to filter the current page on a field's not in the database. So not another roundtrip only the data on the client.

UPDATE

I am adding filters on the client. It works but the resulting sql uses AND, should be OR

On the client:

private async Task OnReadHandler(GridReadEventArgs arg)
    {
        Query.GridRequest = arg.Request;
        var request = Query.GridRequest;
        var searchBoxFilter = request.Filters.SelectMemberDescriptors().Where(x => x.Member == "ProductName").ToList();
        if(searchBoxFilter.Any())
        {
            var clientFilter = new FilterDescriptor{Member = "ClientName", Operator = FilterOperator.Contains, Value = searchBoxFilter.First().Value.ToString()};
            request.Filters.Add(clientFilter);
            var initialsFilter = new FilterDescriptor{Member = "UserInitials", Operator = FilterOperator.Contains, Value = searchBoxFilter.First().Value.ToString()};
            request.Filters.Add(initialsFilter);
        }
        
        var envelope = await TradeOverviewService.GetCertificateTradeRequestsForTradeOverView(Query);
        arg.Data = envelope.CurrentPageData.ToList();
        arg.Total = envelope.TotalItemCount;
    }

Part of the sql


  FROM "IBEX"."V_CERTIFICATE_TRADE_REQUEST" "v"
    WHERE (("v"."FLOW_TYPE" NOT IN (8, 10)) AND ((((LOWER("v"."PRODUCT_NAME_INTERNAL") LIKE '%sydbank%') AND (LOWER("v"."CLIENT_NAME") LIKE '%sydbank%')) AND (LOWER("v"."USER_INITIALS") LIKE '%sydbank%'))))
    ORDER BY "v"."TRADE_DATE" DESC
    OFFSET :p_0 ROWS FETCH NEXT :p_1 ROWS ONLY

So can I create the filters so the resulting sql will be.


  FROM "IBEX"."V_CERTIFICATE_TRADE_REQUEST" "v"
    WHERE (("v"."FLOW_TYPE" NOT IN (8, 10)) AND ((((LOWER("v"."PRODUCT_NAME_INTERNAL") LIKE '%sydbank%') OR (LOWER("v"."CLIENT_NAME") LIKE '%sydbank%')) OR (LOWER("v"."USER_INITIALS") LIKE '%sydbank%'))))
    ORDER BY "v"."TRADE_DATE" DESC
    OFFSET :p_0 ROWS FETCH NEXT :p_1 ROWS ONLY

2 Answers, 1 is accepted

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Dimo
Telerik team
answered on 15 Dec 2023, 07:45 AM

Hi Martin,

By design, all filter descriptors at root level (GridReadEventArgs.Request.Filters.Add(...)) are combined with an AND logical operator. To configure OR filtering, you need to nest several descriptors in a single CompositeFilterDescriptor with an OR.

In your case, the filter descriptor structure should look like this:

CompositeFilterDescriptor
    LogicalOperator: OR
    FilterDescriptors:
        CompositeFilterDescriptor
            LogicalOperator: AND
            FilterDescriptors:
                FilterDescriptor
                    FLOW_TYPE
                FilterDescriptor
                    PRODUCT_NAME_INTERNAL
        FilterDescriptor
            CLIENT_NAME
        FIlterDescriptor
            USER_INITIALS

Note that complex filter structures are usually not compatible with the Grid UI logic and the component is not able to display them to the user. This should not be a problem when you are changing the filters in OnRead, because this is a temporary change that the Grid is not aware of. However, if you need to make the filter structure visible to the user, you need our Filter component.

@using Telerik.DataSource
@using Telerik.DataSource.Extensions

<p>Showing products that a company wants to get rid of. They are:</p>

<ul>
    <li>( No longer in production AND in stock ) OR</li>
    <li>Returned OR</li>
    <li>Damaged</li>
</ul>

<TelerikGrid OnRead="@OnGridRead"
             TItem="@Product"
             Pageable="true"
             Sortable="true">
    <GridColumns>
        <GridColumn Field="@nameof(Product.Name)" Title="Product Name" />
        <GridColumn Field="@nameof(Product.Price)" />
        <GridColumn Field="@nameof(Product.Stock)" />
        <GridColumn Field="@nameof(Product.InProduction)" />
        <GridColumn Field="@nameof(Product.Damaged)" />
        <GridColumn Field="@nameof(Product.Returned)" />
    </GridColumns>
</TelerikGrid>

@code {
    private List<Product> GridData { get; set; } = new();

    private async Task OnGridRead(GridReadEventArgs args)
    {
        await Task.Delay(1);

        args.Request.Filters.Add(new CompositeFilterDescriptor()
        {
            LogicalOperator = FilterCompositionLogicalOperator.Or,
            FilterDescriptors = new FilterDescriptorCollection()
            {
                new CompositeFilterDescriptor()
                {
                    LogicalOperator = FilterCompositionLogicalOperator.And,
                    FilterDescriptors = new FilterDescriptorCollection()
                    {
                        new FilterDescriptor()
                        {
                            Member = nameof(Product.InProduction),
                            MemberType = typeof(bool),
                            Operator = FilterOperator.IsEqualTo,
                            Value = false
                        },
                        new FilterDescriptor()
                        {
                            Member = nameof(Product.Stock),
                            MemberType = typeof(int),
                            Operator = FilterOperator.IsGreaterThan,
                            Value = 0
                        }
                    }
                },
                new FilterDescriptor()
                {
                    Member = nameof(Product.Returned),
                    MemberType = typeof(bool),
                    Operator = FilterOperator.IsEqualTo,
                    Value = true
                },
                new FilterDescriptor()
                {
                    Member = nameof(Product.Damaged),
                    MemberType = typeof(bool),
                    Operator = FilterOperator.IsEqualTo,
                    Value = true
                }
            }
        });

        DataSourceResult result = GridData.ToDataSourceResult(args.Request);

        args.Data = result.Data;
        args.Total = result.Total;
        args.AggregateResults = result.AggregateResults;
    }

    protected override void OnInitialized()
    {
        var rnd = new Random();

        for (int i = 1; i <= 100; i++)
        {
            GridData.Add(new Product()
            {
                Id = i,
                Name = $"Product {i}",
                Price = (decimal)rnd.Next(1, 100),
                Stock = rnd.Next(0, 5),
                InProduction = i % 11 != 0,
                Damaged = i % 13 == 0,
                Returned = i % 17 == 0
            });
        }
    }

    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; } = string.Empty;
        public decimal Price { get; set; }
        public int Stock { get; set; }
        public bool Damaged { get; set; }
        public bool Returned { get; set; }
        public bool InProduction { get; set; }
    }
}

Regards,
Dimo
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Martin Herløv
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answered on 15 Dec 2023, 08:11 AM

Thanks, super example to have as a reference. 

Yesterday I got it to work with the following code. Still wants to know if it's possible to mix server and client filtering.


 private void AddTelerikFiltering(CertificateTradeOverviewQuery query)
    {
        var searchBoxFilter = query.GridRequest.Filters
            .SelectMemberDescriptors()
            .Where(x => x.Member == "ProductName")
            .ToList();
        
        if (searchBoxFilter.Any())
        {
            CompositeFilterDescriptor toRemove = null; 
            foreach (var filterDescriptor1 in query.GridRequest.Filters)
            {
                var compositeFilter = (CompositeFilterDescriptor)filterDescriptor1;
                foreach (var filterDescriptor2 in compositeFilter.FilterDescriptors)
                {
                    var filterDescriptor = (FilterDescriptor)filterDescriptor2;
                    if (filterDescriptor.Member == "ProductName")
                    {
                        toRemove = compositeFilter;
                        break;
                    }
                }
            }
            if(toRemove != null)
                query.GridRequest.Filters.Remove(toRemove);

            var cfd = new CompositeFilterDescriptor { LogicalOperator = FilterCompositionLogicalOperator.Or };
            var clientFilter = new FilterDescriptor
            {
                Member = "ClientName", Operator = FilterOperator.Contains,
                Value = searchBoxFilter.First().Value.ToString()
            };
            var initialsFilter = new FilterDescriptor
            {
                Member = "UserInitials", Operator = FilterOperator.Contains,
                Value = searchBoxFilter.First().Value.ToString()
            };
            var productFilter = new FilterDescriptor
            {
                Member = "ProductName", Operator = FilterOperator.Contains,
                Value = searchBoxFilter.First().Value.ToString()
            };
            cfd.FilterDescriptors.AddRange(new[] { clientFilter, initialsFilter, productFilter });
            query.GridRequest.Filters.Add(cfd);
        }
    }

Dimo
Telerik team
commented on 15 Dec 2023, 08:20 AM

Well, yes, you can apply additional filtering to the data in the DataSourceResult object. You can either use LINQ Where() or execute ToDataSourceResult() again with your own DataSourceRequest argument. However, you will be limited to the collection that you receive from the server, which is usually a single page. Moreover, the logical operator of the additional "client" filters will be always AND with regard to all "server" filters.

Martin Herløv
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commented on 15 Dec 2023, 08:32 AM

Let me understand you right.

You are saying that if I use the filter component I can build filters on values not in the grid.  And Use the filter values to build the grid result from many data sources.

I also have filtering like this


    if (query.ViewDarwinTrades)
        {
            iQuery = iQuery.Where(x => x.ProductInvestmentFund == darwinInvestmentFund);
        }

        if (flowTypes.Any())
        {
            iQuery = iQuery.Where(x => flowTypes.Contains(x.FlowType));
        }

Dimo
Telerik team
commented on 15 Dec 2023, 09:22 AM

The Filter component can produce filter descriptors, which you can use to filter a collection and feed the result to the Grid. The Grid itself has no part in this process, as you can see in the linked online demo.

So, if you have a datasource that can handle the LINQ expression, which will be generated from the Filter component Value, then the answer to your question is "yes".

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