An unhandled exception occurred while processing the request.

[Francesco Pruneri]

Hi there , i have this error with a simple kanban from a sql server table 
My code 

<SfKanban TValue="TodoActivity" KeyField="TodoCode" DataSource="@todoactivitiesDataSource">

    <KanbanColumns>

        <KanbanColumn HeaderText="To Do" KeyField="@(new List<string>() {"Open"})"></KanbanColumn>

        <KanbanColumn HeaderText="In Progress" KeyField="@(new List<string>() {"InProgress"})"></KanbanColumn>

        <KanbanColumn HeaderText="Testing" KeyField="@(new List<string>() {"Testing"})"></KanbanColumn>

        <KanbanColumn HeaderText="Done" KeyField="@(new List<string>() {"Close"})"></KanbanColumn>

    </KanbanColumns>

    <KanbanCardSettings HeaderField="Subject" ContentField="Subject"></KanbanCardSettings>

</SfKanban>

TodoActivity todoactivitynew = new TodoActivity { };

 protected override async Task OnInitializedAsync()

 {

     // Lista delle attività

     todoactivitiesDataSource = await TodoActivityService.SGetActivities();

 }

in the interface 

// tutte le attività

Task<List<TodoActivity>> SGetActivities();

in the class that implements interface 

public async Task<List<TodoActivity>> SGetActivities()

{

    var todoactivities = await _context.TodoActivities

        .Include(x => x.TodoCategories)

        .Include(x => x.TodoTypes)

        .Include(x => x.TodoStatuses)

        .Include(x => x.TodoSources)

        .Include(x => x.Customers)

        .Include(x => x.Projects)

        .Include(x => x.Users)

        .OrderBy(x => x.StartTime)

        .ToListAsync();

    return todoactivities;

}

@todoactivitiesDataSource or  todoactivitiesDataSource it is the same 

I can't understand where it is wrong 

[Vinitha Jeyakumar]

Hi Francesco Pruneri,

Can you please share us with some more details about your reported issue for our better understanding,

• Share the exact issue you are facing with Kanban.
• Share exact issue replication steps along with video illustration.
• Are you facing any exceptions?
• If possible, share us with simple issue replicating runnable sample.

Regards,

Vinitha

[Francesco Pruneri]

hi i can send you files 

An unhandled exception occurred while processing the request.

NullReferenceException: Object reference not set to an instance of an object.

Syncfusion.Blazor.Kanban.SfKanban<TValue>.DataProcess()

• Stack 
• Query 
• Cookies 
• Headers 
• Routing

• NullReferenceException: Object reference not set to an instance of an object.

  • Syncfusion.Blazor.Kanban.SfKanban<TValue>.DataProcess()

  • Syncfusion.Blazor.Kanban.Internal.ProcessData<TContent>.OnParametersSetAsync()

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

  • Microsoft.AspNetCore.Components.Rendering.ComponentState.NotifyCascadingValueChanged(ref ParameterViewLifetime lifetime)

  • Microsoft.AspNetCore.Components.CascadingValue<TValue>.NotifySubscribers(ref ParameterViewLifetime lifetime)

  • Microsoft.AspNetCore.Components.CascadingValue<TValue>.SetParametersAsync(ParameterView parameters)

  • Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)

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

  • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(ref DiffContext diffContext, int oldFrameIndex, int newFrameIndex)

  • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(ref DiffContext diffContext, int oldStartIndex, int oldEndIndexExcl, int newStartIndex, int newEndIndexExcl)

  • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(ref DiffContext diffContext, int oldFrameIndex, int newFrameIndex)

  • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(ref DiffContext diffContext, int oldStartIndex, int oldEndIndexExcl, int newStartIndex, int newEndIndexExcl)

  • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, int componentId, ArrayRange<RenderTreeFrame> oldTree, ArrayRange<RenderTreeFrame> newTree)

  • Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, out Exception renderFragmentException)

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

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

  • Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(int componentId, RenderFragment renderFragment)

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

  • Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()

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

  • Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

  • Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

  • Microsoft.AspNetCore.Components.Endpoints.EndpointHtmlRenderer.WaitForResultReady(bool waitForQuiescence, PrerenderedComponentHtmlContent result)

  • Microsoft.AspNetCore.Components.Endpoints.EndpointHtmlRenderer.RenderEndpointComponent(HttpContext httpContext, Type rootComponentType, ParameterView parameters, bool waitForQuiescence)

  • System.Threading.Tasks.ValueTask<TResult>.get_Result()

  • Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)

  • Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)

  • Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext+<>c+<<InvokeAsync>b__10_0>d.MoveNext()

  • Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)

  • Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

• 
  
  Show raw exception details

  System.NullReferenceException: Object reference not set to an instance of an object.
     at Syncfusion.Blazor.Kanban.SfKanban`1.DataProcess()
     at Syncfusion.Blazor.Kanban.Internal.ProcessData`1.OnParametersSetAsync()
     at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
     at Microsoft.AspNetCore.Components.Rendering.ComponentState.NotifyCascadingValueChanged(ParameterViewLifetime& lifetime)
     at Microsoft.AspNetCore.Components.CascadingValue`1.NotifySubscribers(ParameterViewLifetime& lifetime)
     at Microsoft.AspNetCore.Components.CascadingValue`1.SetParametersAsync(ParameterView parameters)
     at Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)
  --- End of stack trace from previous location ---
     at Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
     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, Exception& renderFragmentException)
     at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
  --- End of stack trace from previous location ---
     at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
     at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(Int32 componentId, RenderFragment renderFragment)
     at Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()
     at Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()
     at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
     at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
     at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
     at Microsoft.AspNetCore.Components.Endpoints.EndpointHtmlRenderer.WaitForResultReady(Boolean waitForQuiescence, PrerenderedComponentHtmlContent result)
     at Microsoft.AspNetCore.Components.Endpoints.EndpointHtmlRenderer.RenderEndpointComponent(HttpContext httpContext, Type rootComponentType, ParameterView parameters, Boolean waitForQuiescence)
     at Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)
     at Microsoft.AspNetCore.Components.Endpoints.RazorComponentEndpointInvoker.RenderComponentCore(HttpContext context)
     at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.<>c.<<InvokeAsync>b__10_0>d.MoveNext()
  --- End of stack trace from previous location ---
     at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
     at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

No query string data.

Variable	Value
.AspNetCore.Antiforgery.HQLn7gSSQmQ	CfDJ8Joie-ICmnhBvtP8dzo8tvNE7ov1Plkbcpz_J39DggIsM_uLnOIep4OOpkKm49H__8DePJrNmZRF4u8vOCb9GlyQPeI0B3s4xR-CzoTZClWxIYnS-m_UJ6oavbHyYmonJk6szedHtcUF2RYcHjqn61Y

Variable	Value
Accept	text/html; blazor-enhanced-nav=on
Accept-Encoding	gzip, deflate, br, zstd
Accept-Language	it-IT,it;q=0.9,en-US;q=0.8,en;q=0.7
Cookie	.AspNetCore.Antiforgery.HQLn7gSSQmQ=CfDJ8Joie-ICmnhBvtP8dzo8tvNE7ov1Plkbcpz_J39DggIsM_uLnOIep4OOpkKm49H__8DePJrNmZRF4u8vOCb9GlyQPeI0B3s4xR-CzoTZClWxIYnS-m_UJ6oavbHyYmonJk6szedHtcUF2RYcHjqn61Y
Host	localhost:7277
Referer	https://localhost:7277/todomanagement
sec-ch-ua	"Google Chrome";v="123", "Not:A-Brand";v="8", "Chromium";v="123"
sec-ch-ua-mobile	?0
sec-ch-ua-platform	"Windows"
sec-fetch-dest	empty
sec-fetch-mode	no-cors
sec-fetch-site	same-origin
User-Agent	Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Endpoint

Name	Value
Display Name	/todomanagement (/todomanagement)
Route Pattern	/todomanagement
Route Order	0
Route HTTP Method	GET, POST

Route Values

No route values.

[Vinitha Jeyakumar]

Hi Francesco Pruneri,

We suspect that the reported issue may occurred due to the missing of data or null values in the data bonded to the Kanban board. So please make sure to avoid null values in the data source added to the Kanban to avoid such exceptions. 

If still issue persists, share us with issue replicating simple runnable sample to validate further.

Regards,

Vinitha