Invalid cast exception after data source update

[Maksim]

Hey

I have a problem while i'm trying to update data source of a dropdown list. 
Here is my component

<EjsDropDownList TValue="int?" Placeholder="SpareName" TItem="SpareNameViewModel" DataSource="@filterSpareNames" ShowClearButton=true>

            <DropDownListFieldSettings Value="Id" Text="Name"></DropDownListFieldSettings>

</EjsDropDownList>

@code {

     private List<SpareNameViewModel> filterSpareNames = new List<SpareNameViewModel>();

     protected override async Task OnInitializedAsync()

     {

            var spareNamesResult = await spareAttributeService.GetSpareNamesAsync();

            if (spareNamesResult.IsSuccess)

            {

                  filterSpareNames = spareNamesResult.Data.ToList();

            }

     }

     public class SpareNameViewModel

    {

        public int Id { get; set; }

        public string Name { get; set; }

    }

}

And below is an exception:

System.InvalidCastException: Unable to cast object of type 'System.Collections.Generic.List`1[System.Int32]' to type 'System.Collections.Generic.IEnumerable`1[System.Object]'.

   at Syncfusion.EJ2.Blazor.BaseComponent.updateProperty[T](String key, T publicValue, T privateValue, Object eventCallback, Expression`1 expression, Boolean isDataSource, Boolean isObservable)

   at Syncfusion.EJ2.Blazor.DropDowns.EjsDropDownList`2.propertyParametersSet()

   at Syncfusion.EJ2.Blazor.DropDowns.EjsDropDownList`2.OnParametersSetAsync()

   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)

   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task)

   at Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.UpdateRetainedChildComponent(DiffContext& diffContext, Int32 oldComponentIndex, Int32 newComponentIndex)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)

   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, Int32 componentId, ArrayRange`1 oldTree, ArrayRange`1 newTree)

   at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderInExistingBatch(RenderQueueEntry renderQueueEntry)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()

--- End of stack trace from previous location where exception was thrown ---

   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessPendingRender()

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(Int32 componentId, RenderFragment renderFragment)

   at Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()

   at SC.ClientApp.Blazor.Pages.Main.OnInitializedAsync() in D:\Repositories\SC\sc.clientapp.blazor\SC.ClientApp.Blazor\Pages\Main.razor:line 177

   at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessAsynchronousWork()

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderRootComponentAsync(Int32 componentId, ParameterView initialParameters)

   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.CreateInitialRenderAsync(Type componentType, ParameterView initialParameters)

   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.RenderComponentAsync(Type componentType, ParameterView initialParameters)

   at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.<>c__11`1.<<InvokeAsync>b__11_0>d.MoveNext()

Did I miss anything?

[Sureshkumar P]

Hi Maksim, 

 

Greetings from Syncfusion support. 

 

Based on your shared information with code example and error details, we suspect that the issue caused due to define the same classes in two places (model and in component “SpareNameViewModel”). We suggest you remove the SpareNameViewModel class from the component rendering page and inherit the model class to resolve the problem.  

 

We have created the sample based on your requirement. please find the sample here: https://www.syncfusion.com/downloads/support/directtrac/general/ze/DropDownDataSource-365733169  

 

If still you have facing the same issue. Please revert us with below details. 

1.     Share your service result data  

2.     If possible, please reproduce the issue in our abive attached sample, and explain the detailed issue reproducing steps. 

These details will help us to provide exact solution at earliest. 

 

Regards, 

Sureshkumar P