Last Updated: 13 May 2022 12:02 by ADMIN

Hi, after Updating to the latest version I'm getting this error:

System.InvalidOperationException: Headers are read-only, response has already started.
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.ThrowHeadersReadOnlyException()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpResponseHeaders.Microsoft.AspNetCore.Http.IHeaderDictionary.set_ContentType(StringValues value)
   at Microsoft.AspNetCore.Http.DefaultHttpResponse.set_ContentType(String value)
   at Microsoft.AspNetCore.Mvc.Formatters.OutputFormatter.WriteResponseHeaders(OutputFormatterWriteContext context)
   at Microsoft.AspNetCore.Mvc.Formatters.TextOutputFormatter.WriteAsync(OutputFormatterWriteContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor.ExecuteAsyncCore(ActionContext context, ObjectResult result, Type objectType, Object value)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor.ExecuteAsync(ActionContext context, ObjectResult result)
   at Microsoft.AspNetCore.Mvc.ObjectResult.ExecuteResultAsync(ActionContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultAsync>g__Logged|22_0(ResourceInvoker invoker, IActionResult result)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeAlwaysRunResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Als.ALSolutions.WebSite.Startup.<>c__DisplayClass13_0.<<Configure>b__3>d.MoveNext() in C:\ALS_Git\ALSolutions V2\ALSolutions_V2\Als.ALSolutions.WebSite\Startup.cs:line 615


  1. Request URL:
  2. Request Method:


Last Updated: 04 Apr 2022 13:39 by ADMIN
Created by: Robert
Comments: 1
Type: Feature Request

Ability to split sections for use in Conditions and Formatting.

Example: Detail split into Detail-A and Detail-B where either or both may display based on a condition defined at the Section Split level.

For Crystal Report users (myself since 2008) this is a very important feature.

It allows a single report be used for detail or summary reporting as well as multiple conditions for display.

This is an example from CR:

Last Updated: 18 Feb 2022 15:50 by ADMIN


The Telerik Reporting REST service with CubeDataSource component that now can only be used with the .NET Framework.

We'd like to request that this component for .NET Core 6.

Thanks in advance.

Last Updated: 26 Jan 2022 07:51 by ADMIN
Created by: Ryan
Comments: 1
Type: Feature Request

I have a request that probably doesn't require much explanation. It would be helpful to allow comments in expressions created via the standalone designer to help explain particularly complex and infrequently encountered logic.


Last Updated: 14 Jan 2022 14:25 by ADMIN
Please.  Please.  Please add a setting that opens the Preview in Print Layout by default instead of Interactive Layout.  I understand the difference.  I understand that Interactive opens faster, but it is almost impossible for me to explain to my end-users why the preview doesn't actually look like the printed version until you click another button to toggle to Print Preview.  I hope you will consider this so that the hate mail in my inbox decreases.  :)
Last Updated: 06 Jan 2022 15:48 by ADMIN

When a report includes drill-down item(s), the report is run again each time the user expands a drill down item.  This is apparent in the demo at

I would like to see all of the drill-down data generated and delivered with the initial report, but collapsed and awaiting inspection.

Perhaps this would be an attribute of the drill-down element (pre-fetch versus re-run) so that developers can choose the most appropriate experience for their users  / conserve server resources.

Last Updated: 27 Dec 2021 07:32 by ADMIN
Created by: Shawn
Comments: 1
Type: Feature Request
Integrate a SSRS report viewer that can be used in a Blazor Server application.
Last Updated: 13 Dec 2021 14:17 by ADMIN
I have websites that contain different kinds of Telerik reports. They are rendered in the HTML5ReportViewer control.  Some reports need to go to special label printers.  Other reports need to go to standard laser printers.  It would be a lot easier on the users (and waste less paper) if the website could set the default printer for each report so the users do not have to remember to change to the correct printer.
Last Updated: 10 Dec 2021 07:38 by ADMIN
When you export a report from VBA, the image is missing in the PDF file. It is important that the problem is reproducible only on machines that Telerik Reporting has never been installed. With the same code, when exporting from VS, the report is correctly exported. The attached PDF files represent the outcome from both exports.
Last Updated: 16 Nov 2021 12:24 by ADMIN
Created by: Bernard
Comments: 1
Type: Feature Request


It would be very practical to have a component that could display HTML and CSS code from a data source.


Thank you


Last Updated: 04 Nov 2021 07:26 by ADMIN

Currently there appears to be no functionality available to add additional attachments via the Telerik Reporting Send Mail dialog or programmatically by passing parameters to the Report Viewer using a model.


Scenario 1:

- When we email a new Quote, which is a Telerik Report, to a Customer we would like to automatically attach a "New Products Brochure". The brochure is a frequently updated pdf document that would reside on the server.


Scenario 2:

- When we email a Customer Invoice, which is a Telerik Report, to a Customer if:

1) It is the 1st Invoice we have sent them for the current Agreement then automatically attach the Agreement related to Invoice - where the Agreement is another Telerik Report.

2) The Customer has an outstanding balance with us then attach a "Customer Statement", which is another Telerik Report, in pdf format.


Thanks in advance.


Last Updated: 07 Oct 2021 12:24 by ADMIN
Created by: Stéphane
Comments: 1
Type: Feature Request


I would like to know if it's possible to reconsider this request, or at least to leave it open for a longer period of time so people can vote. It would be really nice to be able to integrate existing SSRS reports. We have a lot, I really mean a lot, of SSRS reports. We believe using another third party would just make our "ecosystem" more heterogeneous.

I'm pretty sure we're not alone with tons of SSRs reports that are waiting for a seamless integration with Telerik UI for Blazor.

Thanks in advance

Stéphane Roy



Last Updated: 27 Sep 2021 15:50 by ADMIN
If there is an error when connecting to the database there will be no data returned and instead of displaying an informative error message, the report will be displayed as 'No page to display' by the designer/viewer, or exported as a corrupted document by the ReportProcessor.
The error will be displayed when SkipBlankPages is False.
Last Updated: 20 Sep 2021 13:27 by ADMIN

The Margins property cannot be set in the Blazor wrapper of the Web Report Designer:


Last Updated: 10 Sep 2021 06:33 by Rahul
Created by: Mhd.Ahd
Comments: 2
Type: Feature Request
When using multi-child select statement like the below:

SELECT ORG, C1, C2, ... FROM (
   (SELECT X FROM Y WHERE Z1 = xxx AND Z2 = :param1 AND DATE BETWEEN :param2 AND :param3) C1,
   (SELECT X FROM Y WHERE Z1 = yyy AND Z2 = :param1 AND DATE BETWEEN :param2 AND :param3) C2,
Then binding with report parameter will be like:
param1 = rpt_param1
param2 = rpt_param2
param3 = rpt_param3

The an error occurred while excuting the query in the datasource wizard.
Also, some time the wizard accepts the query but the preview mode will display the same error.
The error is "ORA-01008 : Not all variables bound"

Workaround: Don't use the same query parameter in more than one child select statement. Create new datasource parameters per each select statement; then bind them all to the same report parameter. 

SELECT ORG, C1, C2, ... FROM (
   (SELECT X FROM Y WHERE Z1 = xxx AND Z2 = :param11 AND DATE BETWEEN :param12 AND :param13) C1,
   (SELECT X FROM Y WHERE Z1 = yyy AND Z2 = :param21 AND DATE BETWEEN :param22 AND :param23) C2,
Then binding with report parameter will be like:
param11 = rpt_param1
param21 = rpt_param1
param12 = rpt_param2
param22 = rpt_param2
param13 = rpt_param3
param23 = rpt_param3
* Report Designer v2014.Q2
* Oracle Database 10g1, 10g2 or 12c
* Oracle Client: ODTwithODAC Or Less
Last Updated: 23 Aug 2021 14:31 by ADMIN
Created by: Thanh
Comments: 0
Type: Bug Report

I followed How to set up in Blazor application | Telerik Reporting

All done! But when it run i got an error "telerikWebReportDesignerInterop.js 404"

<script src="_content/telerik.webreportdesigner.blazor/telerikWebReportDesignerInterop.js" defer></script>

and in console show:

fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
      Unhandled exception in circuit 'Gyr8E4g_PwQHf7G2UKY2h3obMpujPfFp2x9i7dkB4oQ'.
      Microsoft.JSInterop.JSException: Could not find 'telerikWebReportDesignerInterop.createWebReportDesignerWidget' ('telerikWebReportDesignerInterop' was undefined).
Error: Could not find 'telerikWebReportDesignerInterop.createWebReportDesignerWidget' ('telerikWebReportDesignerInterop' was undefined).
    at https://localhost:5001/_framework/blazor.server.js:1:67713
    at Array.forEach (<anonymous>)
    at e.findFunction (https://localhost:5001/_framework/blazor.server.js:1:67673)
    at v (https://localhost:5001/_framework/blazor.server.js:1:69415)
    at https://localhost:5001/_framework/blazor.server.js:1:70361
    at new Promise (<anonymous>)
    at e.beginInvokeJSFromDotNet (https://localhost:5001/_framework/blazor.server.js:1:70334)
    at https://localhost:5001/_framework/blazor.server.js:1:26441
    at Array.forEach (<anonymous>)
    at e.invokeClientMethod (https://localhost:5001/_framework/blazor.server.js:1:26411)
         at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](Int64 targetInstanceId, String identifier, Object[] args)
         at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)
         at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

Telerik Reporting

<PackageReference Include="Telerik.Reporting.Services.AspNetCore" Version="" />
<PackageReference Include="Telerik.Reporting.OpenXmlRendering" Version="" />
<PackageReference Include="Telerik.ReportViewer.Blazor" Version="" />
<PackageReference Include="Telerik.WebReportDesigner.Blazor" Version="" />
<PackageReference Include="Telerik.WebReportDesigner.Services" Version="" />



namespace CSharp.Net5.BlazorIntegrationDemo
    using Microsoft.AspNetCore.Builder;
    using Microsoft.AspNetCore.Hosting;
    using Microsoft.Extensions.Configuration;
    using Microsoft.Extensions.DependencyInjection;
    using Microsoft.Extensions.DependencyInjection.Extensions;
    using Microsoft.Extensions.Hosting;
    using System;
    using Telerik.Reporting.Cache.File;
    using Telerik.Reporting.Services;
    using Telerik.WebReportDesigner.Services;

    public class Startup
        public Startup(IConfiguration configuration)
            this.Configuration = configuration;

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit
        public void ConfigureServices(IServiceCollection services)


            // Configure dependencies for ReportsController.
            services.TryAddSingleton<IReportServiceConfiguration>(sp =>
                new ReportServiceConfiguration
                    ReportingEngineConfiguration = sp.GetService<IConfiguration>(),
                    HostAppId = "Net5BlazorDemo",
                    Storage = new FileStorage(),
                    ReportSourceResolver = new UriReportSourceResolver(System.IO.Path.Combine(sp.GetService<IWebHostEnvironment>().ContentRootPath, "..", "..", "..", "..", "Report Designer", "Examples")),

            // Configure dependencies for ReportDesignerController.
            services.TryAddSingleton<IReportDesignerServiceConfiguration>(sp => new ReportDesignerServiceConfiguration
                DefinitionStorage = new FileDefinitionStorage(
                    System.IO.Path.Combine(sp.GetService<IWebHostEnvironment>().ContentRootPath, "..", "..", "..", "..", "Report Designer", "Examples")),
                SettingsStorage = new FileSettingsStorage(
                    System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "Telerik Reporting")),
                ResourceStorage = new ResourceStorage(
                    System.IO.Path.Combine(sp.GetService<IWebHostEnvironment>().ContentRootPath, "..", "..", "..", "..", "Report Designer", "Examples", "Resources"))

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
            if (env.IsDevelopment())

            app.UseEndpoints(endpoints =>

        /// <summary>
        /// Loads a reporting configuration from a specific JSON-based configuration file.
        /// </summary>
        /// <param name="environment">The current web hosting environment used to obtain the content root path</param>
        /// <returns>IConfiguration instance used to initialize the Reporting engine</returns>
        static IConfiguration ResolveSpecificReportingConfiguration(IWebHostEnvironment environment)
            // If a specific configuration needs to be passed to the reporting engine, add it through a new IConfiguration instance.
            var reportingConfigFileName = System.IO.Path.Combine(environment.ContentRootPath, "reportingAppSettings.json");
            return new ConfigurationBuilder()
                .AddJsonFile(reportingConfigFileName, true)


@page "/webreportdesigner"
@using Telerik.WebReportDesigner.Blazor

    #wrd1 {
        position: relative;
        height: 880px;
        padding-right: 50px;

@* Create the WebReportDesignerWidget *@

<p>This Web Report Designer instance works with reports hosted locally using the Reporting REST service. For more information, visit the <a target="_blank" href="">Web Report Designer</a> article.</p>
<WebReportDesigner DesignerId="wrd1"
                   ToolboxArea="new ToolboxAreaOptions() { Layout = ToolboxAreaLayout.List }"
                   PropertiesArea="new PropertiesAreaOptions() { Layout = PropertiesAreaLayout.Categorized }" />

Last Updated: 22 Jun 2021 10:52 by ADMIN


I am using Telerik Report Designer

I have created a Web Service Datasource:

The returned Raw String in Preview Data in the Wizard:


 "Ordinal": 0,
 "Cardinality": 1,
 "Tuples": [
     "Ordinal": 0,
     "Members": [
         "Name": "Total ProfitLossBalance"

Everything appears to work, however the Datasource returns an Error:

System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
   bei Telerik.Reporting.Processing.WebServiceDataSource.WebServiceClient.SendCore(IWebServiceRequestSettings settings, AuthenticationHeaderValue authHeader, HttpClient httpClient, HttpClientHandler httpClientHandler)
   bei Telerik.Reporting.Processing.WebServiceDataSource.WebServiceClient.Request(WebServiceDataSource processedDS)
   bei Telerik.Reporting.Processing.WebServiceDataSource.WebServiceDataProvider.GetRemoteRawData(WebServiceDataSource processedDS)
   bei Telerik.Reporting.Processing.WebServiceDataSource.WebServiceDataProvider.get_RawData()
   bei Telerik.Reporting.Processing.WebServiceDataSource.WebServiceSchemaAdapter.AddDataMeasures(SimpleDataModel model)
   bei Telerik.Reporting.Processing.Data.SimpleSchemaAdapterBase.Fill(SimpleDataModel model)
   bei Telerik.Reporting.Processing.Data.SimpleDataProvider`1.GetSchemaCore()
   bei Telerik.Reporting.Processing.Data.DataProvider`1.Telerik.Reporting.Processing.Data.IDataProvider.GetSchema()
   bei Telerik.Reporting.Data.Design.DataSourceService.GetLocalSchema(IDataSource datasource, IDataProviderContext dataProviderContext)
   bei Telerik.Reporting.Data.Design.DataSourceDesignerBase.Telerik.Reporting.Design.Interfaces.IDataSchemaProvider.GetSchema()
   bei Telerik.Reporting.Data.Design.DataSourceService.GetSchemaFromContext(Object context)
   bei Telerik.Reporting.Data.Design.DataSourceService.Telerik.Reporting.Design.Interfaces.IDataSourceService.GetCurrentDataItemSchema(Boolean getFromParentRecursively)
   bei Telerik.Reporting.Design.DataExplorerControl.<>c__DisplayClass2.<RefreshDataSource>b__0()
Last Updated: 11 Jun 2021 07:22 by ADMIN

Figure 1 report is generated using the data source in figure 2. Data in column "Value2" is mapped to the column Text in the generated report.

In the below-generated report, text in row one "Default CUS for CDV" is truncated. A feature to make the user know there is more data to be shown will be great.

Figure 1

Figure 2



So, Adding an option to display an indicator such as “...” for truncated strings so that the viewers get to know there is more information to be displayed

Provide an option to absolute break (display until last possible character) of the string rather than word-wrapping if there’s more content than the text box width.

Last Updated: 01 Jun 2021 14:59 by ADMIN

Hi Team,

Thanks for your regular support.

I Want to hide the GroupFooterSection if I don't have any data to be displayed(zero records found case).

Please let me know the solution for the above case.


Ausfleet Team.



Last Updated: 28 Apr 2021 14:32 by ADMIN
Created by: Revanth
Comments: 1
Type: Feature Request

Hi, how to create variable column width in programmatically created table? means how to adjust the width of the column based on dynamic data?

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