Multiselect Problem with DataAdapter and Virtualization

[Daniel]

Hi, i'm using a MultiSelect and it's firing the method to load data at initialize, but this is not the normal behavior for the DropDown and Combobox

The problem is that at initial Load it does grab all records, slowing down

I'v set the EnableVirtualization to true and ItemsCount as 10 but it doesn't seems to affect the first data load

this is the configuration i'm using:

<SfMultiSelect TValue="List<UsuarioViewModel>" TItem="UsuarioViewModel" Mode="@VisualMode.CheckBox" AllowCustomValue=false

                          @bind-Value="@PostoTrabalho.UsuariosPermitidos" AllowFiltering=true ShowSelectAll="true" ShowClearButton="true"

                            @ref="@MultiUsuarios" EnableVirtualization="true" ItemsCount="10" Placeholder="@Language.Usuarios">

                              <MultiSelectTemplates TItem="UsuarioViewModel">

                                 <ItemTemplate Context="usuarioContext">

                                    <span class='name'>

                                       <span class="fullname">@((usuarioContext as UsuarioViewModel).NomeCompleto)</span>

                                       <span class="username">@((usuarioContext as UsuarioViewModel).NomeUsuario)</span>

                                    </span>

                                 </ItemTemplate>                                

                              </MultiSelectTemplates>                              

                              <MultiSelectFieldSettings Text="NomeUsuario" Value="Id" ></MultiSelectFieldSettings>

                              <MultiSelectEvents TValue="List<UsuarioViewModel>" TItem="UsuarioViewModel" Filtering="OnFilter"></MultiSelectEvents>                              

                              <SfDataManager Adaptor="Adaptors.CustomAdaptor">

                                 <DataAdaptorComponent TModel="UsuarioViewModel" Action="Usuario/ListarAtivo">

                                 </DataAdaptorComponent>

                              </SfDataManager>

                        </SfMultiSelect>

Note that on the first load of Data the Skip and Take are 0:

The list contains around 600 items, so it's to heavy to the UI

Shouldn't the virtualization enabled make the component call just the data t

[Daniel]

Also, is there a feature request for the DropDowns, Combox and Multiselect to have a

ImmediateModeDelay property on filters like Grids have?

[Deepak Ramakrishnan]

Hi Daniel, 

  

Greetings from syncfusion support. 

  

  

We are currently recreating the expected scenerio from your end to reproduce the issue you are facing . We will update the possible details in two business days (2nd November 2021) .We appreciate your patience until then. 

  

Thanks, 

Deepak R. 

[Deepak Ramakrishnan]

Hi Daniel, 

 

Thanks for your patience. 

 

We have created a sample with custom adapter with virtualization feature as per your requirement kindly refer it for your reference. 

 

 

<div id="ControlRegion"> 

    <SfDropDownList TValue="string" TItem="Order" Query="@Query" EnableVirtualization="true"> 

        <SfDataManager AdaptorInstance="@typeof(CustomAdaptor)" Adaptor="Adaptors.CustomAdaptor"></SfDataManager> 

        <DropDownListFieldSettings Value="@nameof(Order.OrderID)" Text="@nameof(Order.CustomerID)"></DropDownListFieldSettings> 

    </SfDropDownList> 

 

</div> 

 

 

@code{ 

    public Query Query = new Query().Take(20); 

    protected override void OnInitialized() 

    { 

        //Orders = dbContext.Orders.ToList(); 

    } 

    public class CustomAdaptor : DataAdaptor 

    { 

        public OrderContext dbcontext { get; set; } 

        public CustomAdaptor(OrderContext orderContext) 

        { 

            dbcontext = orderContext; 

        } 

        // Performs data Read operation 

        public override object Read(DataManagerRequest dm, string key = null) 

        { 

            IEnumerable<Order> DataSource = dbcontext.Orders; 

            if (dm.Search != null && dm.Search.Count > 0) 

            { 

                // Searching 

                DataSource = DataOperations.PerformSearching(DataSource, dm.Search); 

            } 

            if (dm.Sorted != null && dm.Sorted.Count > 0) 

            { 

                // Sorting 

                DataSource = DataOperations.PerformSorting(DataSource, dm.Sorted); 

            } 

            if (dm.Where != null && dm.Where.Count > 0) 

            { 

                // Filtering 

                DataSource = DataOperations.PerformFiltering(DataSource, dm.Where, dm.Where[0].Operator); 

            } 

            int count = dbcontext.Orders.Count(); 

            if (dm.Skip != 0) 

            { 

                //Paging 

                DataSource = DataOperations.PerformSkip(DataSource, dm.Skip); 

            } 

            if (dm.Take != 0) 

            { 

                DataSource = DataOperations.PerformTake(DataSource, dm.Take); 

            } 

            return dm.RequiresCounts ? new DataResult() { Result = DataSource, Count = count } : (object)DataSource; 

        } 

    } 

} 

 

 

 

 

Sample Link :  https://www.syncfusion.com/downloads/support/forum/168995/ze/SyncfusionBlazorApp1-490649615 

 

If this does not meet your requirement kindly provide the following details to proceed further 

 

1.Simple code sample or modify the provided sample as per your requirement to reproduce the issue 

2.If any replication procedure followed to reproduce the issue. 

 

The above details will help us to analyze and provide you the better solution. 

 

Thanks, 

Deepak R.