SearchTemplate Context NullReferenceException

[KisaPs]

I'm trying to do a search from a drop-down list

<Table TItem="CostPriceModel" @ref="TableColumnVisible"
   ShowSearch="true" 
   ShowAdvancedSearch ="true"
   SearchMode="SearchMode.Popup"
   SearchModel="@SearchModel"
   OnSaveAsync="@OnSaveAsync"
   OnQueryAsync="@OnQueryAsync"
   ......
>
....
<TableColumn @bind-Field="@context.SubjectName" Searchable="true">
    <SearchTemplate Context="model">
         <div class="col-12 col-sm-6">
            <Select Items="SearchItemsCategory" @bind-Value="@model.SubjectName" ShowLabel="true" DisplayText="Find" />
        </div>
    </SearchTemplate>
</TableColumn>
....
<Table/>

With direct declaration of values, everything works successfully.

@code {
   private CostPriceModel? SearchModel { get ; set; } = new CostPriceModel();
   IEnumerable<SelectedItem>? SearchItemsCategory { get; set; } = new List<SelectedItem> { new SelectedItem { Text="Text", Value = 
   "Value"} };

}

But as soon as I need to get this data from the database, an error occurs.

 protected override async Task OnInitializedAsync()
 {
     SearchItemsCategory = await repository.GetSearchItems().Select(c => new SelectedItem { Value = c.Key, Text = c.Key }));
 }

I also tried assigning it to SetParametersAsync(). Also to no avail.
So I can't asynchronously receive data to use for searching and filtering?

warn: Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer[100]
      Unhandled exception rendering component: Object reference not set to an instance of an object.
      System.NullReferenceException: Object reference not set to an instance of an object.
         at BootstrapBlazor.Components.Select`1.<ResetSelectedItem>b__111_0(SelectedItem i)
         at System.Collections.Generic.List`1.Find(Predicate`1 match)
         at BootstrapBlazor.Components.Select`1.ResetSelectedItem()
         at BootstrapBlazor.Components.Select`1.<BuildRenderTree>b__119_1(RenderTreeBuilder __builder2)
         at Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder.AddContent(Int32 sequence, RenderFragment fragment)
         at BootstrapBlazor.Components.RenderTemplate.BuildRenderTree(RenderTreeBuilder __builder)
         at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Components.ErrorBoundaryBase.Microsoft.AspNetCore.Components.IErrorBoundary.HandleException(Exception exception)
         at Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)
fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
      Unhandled exception in circuit 'UvXfpm71osoM8tua1FuTCPKu9mQBFsp7BV3OIpILzG4'.
      System.NullReferenceException: Object reference not set to an instance of an object.
         at BootstrapBlazor.Components.Select`1.<ResetSelectedItem>b__111_0(SelectedItem i)
         at System.Collections.Generic.List`1.Find(Predicate`1 match)
         at BootstrapBlazor.Components.Select`1.ResetSelectedItem()
         at BootstrapBlazor.Components.Select`1.<BuildRenderTree>b__119_1(RenderTreeBuilder __builder2)
         at Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder.AddContent(Int32 sequence, RenderFragment fragment)
         at BootstrapBlazor.Components.RenderTemplate.BuildRenderTree(RenderTreeBuilder __builder)
         at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Components.ErrorBoundaryBase.Microsoft.AspNetCore.Components.IErrorBoundary.HandleException(Exception exception)
         at Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)

[ArgoZhang]

@KisaPs hi. try this code

<TableColumn @bind-Field="@context.SubjectName" Searchable="true">
    <SearchTemplate Context="model">
         <div class="col-12 col-sm-6">
            <CustomFilter Context="@context"></CustomFilter>
        </div>
    </SearchTemplate>
</TableColumn>

CustomFilter.razor

<Select Items="SearchItemsCategory" @bind-Value="@model.SubjectName" ShowLabel="true" DisplayText="Find" />

@code {
 protected override async Task OnInitializedAsync()
 {
     SearchItemsCategory = await repository.GetSearchItems().Select(c => new SelectedItem { Value = c.Key, Text = c.Key }));
 }
}

[KisaPs]

For some reason the error is the same ....

[densen2014]

SearchItemsCategory has items?

Can you take a screenshot of the debugging interface to see SearchItemsCategory has data?

[KisaPs]

Yes, there is data

[ArgoZhang]

@KisaPs please provide a mini-project for repro this issue. database use sqlite.

[KisaPs]

I created a mini-project, but I couldn't repeat the problem. Everything works. Where is the reason for the error I cannot understand

[KisaPs]

Thanks anyway.