RadzenDataFilterProperty with RadzenDropDown: Error when adding filter

When I use RadzenDataFilterProperty with a RadzenDropDown only once within a RadzenDataFilter, everything works fine. But when I add more RadzenDataFilterProperties, I sometimes run into "Unhandled exception rendering component: No applicable method 'Contains' exists in type 'Object'."
The error occurs in this scenario: First, I click on the "+" for adding a new filter row. I can select the property I want to filter, and then I select the values I want to include in the filter. Everythings is OK, the DataGrid shows only the filtered data. After this, I click again on the "+" for another filter row to be added. I select the second property and when clicking into the dropdown to select the values, the error occurs.
The Problem is not the second RadzenDataFilterProperty itself! I do have three different RadzenDataFilterProperty with RadzenDropDown, and no matter how i arrange them: the error occurs mostly at the second row. No matter which property is choosen in the first or in the second. If I do have only one of this RadzenDataFilterProperty with RadzenDropDown (in code), it is working. Each of the them.

And now the curious thing: Sometimes there is no Error in the second row. I'm able to select values and the selection is applied to the datagrid. But after adding the third row and click into the dropdown-list, the same Error occurs.

What am I doing wrong here?

(Code is shown with two of the RadzenDataFilterProperties)

                <RadzenDataFilter @ref="DataFilter" Auto="true" Data="@ListOfTubes" TItem="TubeEntity" ViewChanged=@(view => FilteredListOfTubes = view.ToList())>
                    <Properties>
                        <RadzenDataFilterProperty TItem="TubeEntity" Property="STUDYNUMBER" Title="Studynumber" FilterValue="@selectedStudynumbers" 
                            Type="typeof(IEnumerable<string>)" FilterOperator="FilterOperator.Contains">
                            <FilterTemplate>
                                 <RadzenDropDown @bind-Value=@selectedStudynumbers Style="width:100%;"
                                    Change=@OnSelectedStudynumbersChange Data="@(ListOfStudynumbers)" AllowClear="true" Multiple="true" />
                            </FilterTemplate>
                        </RadzenDataFilterProperty>
                        <RadzenDataFilterProperty TItem="TubeEntity" Property="DEPARTMENT" Title="Department"  FilterValue="@selectedDepartments" 
                            Type="typeof(IEnumerable<string>)" FilterOperator="FilterOperator.Contains">
                            <FilterTemplate>
                                 <RadzenDropDown @bind-Value=@selectedDepartments Style="width:100%;"
                                    Change=@OnSelectedDepartmentChange Data="@(ListOfDepartments)" AllowClear="true" Multiple="true" />
                            </FilterTemplate>
                        </RadzenDataFilterProperty>
                    </Properties>
                </RadzenDataFilter>
				
	<RadzenDataGrid @ref="@DataGrid" Data="@(FilteredListOfTubes ?? ListOfTubes)" TItem="TubeEntity" AllowFiltering="true" PageSize="50" AllowPaging="true" AllowSorting="true" FilterMode="FilterMode.Advanced"  AllowColumnResize="true">
        <Columns>
			...
        </Columns>
    </RadzenDataGrid>

@code {
	[Parameter}
	public List<TubeEntity> ListOfTubes { get; set; }
	
    List<TubeEntity> FilteredListOfTubes;

    IEnumerable<string> ListOfDepartments;
    IEnumerable<string> ListOfStudynumbers;

    IEnumerable<string> selectedDepartments;
    IEnumerable<string> selectedStudynumbers;

    RadzenDataGrid<TubeEntity> DataGrid = new RadzenDataGrid<TubeEntity>();
    RadzenDataFilter<TubeEntity> DataFilter = new RadzenDataFilter<TubeEntity>();

    protected override async Task OnInitializedAsync()
    {
        ListOfDepartments = ListOfTubes.Select(x => x.DEPARTMENT).Distinct();
        ListOfStudynumbers = ListOfTubes.Select(x => x.STUDYNUMBER).Distinct();
    }

    private void OnSelectedDepartmentChange(object value)
    {
        if (selectedDepartments != null && !selectedDepartments.Any())
        {
            selectedDepartments = null;  
        }
    }

    private void OnSelectedStudynumbersChange(object value)
    {
        if (selectedStudynumbers != null && !selectedStudynumbers.Any())
        {
            selectedStudynumbers = null;  
        }
    }
}

We will need runnable code where we can reproduce the problem.

I just cloned RadzenBlazorDemos.Server project from github and run it locally... its the same error: go to Datafilter, add a second row, dont select a value and add a third row.

The key is obviously to not choose a value, but clicking the plus again...

It happens also at the published website:

Thanks! Fixed immediately and the fix will be part of our next update Monday.

Nice, thanks a lot for the fast fix!

Isn't fixed with today's update (4.3.8)

There hasn't been a release of Radzen.Blazor today (yet).

alright, i see... sorry :slight_smile: