Sorry, below the component is called TelerikGridFilter.razor

Here's how I've implemented it if it helps anyone whilst waiting, this is just for List<string>:

I created a new component to handle the filter

<div class="filter-values-container">
    @if (Data != null)
    {
        foreach (var item in Data)
        {
            <div class="mb-1">
                @{
                    string label = string.IsNullOrEmpty(item) ? "Not set" : item;
                }
                <TelerikCheckBox Value="@(GetFilterValues(Context.FilterDescriptor).Contains(item))"
                         Id="@($"name_{label}")"
                         ValueChanged="@((bool value) => ColumnValueChanged(value, item, Field, Context.FilterDescriptor))">
                </TelerikCheckBox>
                <label for="@($"name_{label}")" class="ms-1">@label</label>
            </div>
        }
    }
</div>

@code {
    [Parameter] public string Field { get; set; } = null!;
    [Parameter] public List<string>? Data { get; set; }
    [Parameter] public FilterMenuTemplateContext Context { get; set; } = null!;

    /// <summary>
    /// Telerik Grid filtering
    /// </summary>
    /// <param name="filterDescriptor"></param>
    /// <returns></returns>
    private static List<string> GetFilterValues(CompositeFilterDescriptor filterDescriptor)
    {
        return filterDescriptor.FilterDescriptors.Select(f => (f as FilterDescriptor)!.Value?.ToString()).ToList()!;
    }

    /// <summary>
    /// Telerik Grid filtering
    /// </summary>
    /// <param name="value"></param>
    /// <param name="itemValue"></param>
    /// <param name="columnName"></param>
    /// <param name="filterDescriptor"></param>
    private static void ColumnValueChanged(bool value, string itemValue, string columnName, CompositeFilterDescriptor filterDescriptor)
    {
        var filter = filterDescriptor.FilterDescriptors.FirstOrDefault(f => (f as FilterDescriptor)!.Value?.ToString() == itemValue);

        filterDescriptor.LogicalOperator = FilterCompositionLogicalOperator.Or;

        if (value && filter == null)
        {
            filterDescriptor.FilterDescriptors.Add(new FilterDescriptor(columnName, FilterOperator.IsEqualTo, itemValue));
        }
        else if (!value && filter != null)
        {
            filterDescriptor.FilterDescriptors.Remove(filter);
        }
    }
}

 

Get the data needed for the filters

prospects = await Http.GetFromJsonAsync<List<ProspectSummaryViewModel>>("Prospect/AllProspects");
            if (prospects != null && prospects.Any())
            {
                professions = prospects.Select(x => x.Profession).OrderBy(x => x).Distinct().ToList()!;
                applicationTypes = prospects.Select(x => x.ApplicationType).OrderBy(x => x).Distinct().ToList()!;
            }

 

And add the Filter to the Column

 

            <GridColumn Field="@(nameof(ProspectSummaryViewModel.Profession))" Width="100px" Groupable="false">
                <FilterMenuTemplate>
                    <TelerikGridFilter Context="@context" Field="@(nameof(ProspectSummaryViewModel.Profession))" Data="@professions" />
                </FilterMenuTemplate>
            </GridColumn>
            <GridColumn Field="@(nameof(ProspectSummaryViewModel.ApplicationType))" Width="120px" Groupable="false">
                <FilterMenuTemplate>
                    <TelerikGridFilter Context="@context" Field="@(nameof(ProspectSummaryViewModel.ApplicationType))" Data="@applicationTypes" />
                </FilterMenuTemplate>
            </GridColumn>

FilterSortOrder.Ascending

FilterSortOrder.Descending

FilterSortOrder.None

perhaps?

Bump to this! :)

 

Yes - having it sort ascending would emulate "Excel-like" filtering behavour.

 

Also, imagine a very long list, then the check-box column becomes non-functional as you will need to use the search.

See small example attached where the user wants to look down a list to find inventory items only within "OEG" crates.

 

 

Or a list of documents that have a sequential number;

 

 

 

 

 

Or imagine a list of names of people and you want to find if someone exists - noting that sometimes, filters are used by the user as a check to see if a value exists before drilling down.

 

Regards

Phil