ReportDesigner - is it possible to restrict "Build new data connections" and allow to use only "Select from existing data connections" ?

This question is regarding "Configure XXX_DataSource" window:

Hello, I'm new to web development, and I'm currently facing an issue with viewing reports on my website when it's uploaded to the server using IIS. The problem is that sometimes I can't view the Report Viewer, but other times I can. When I can't view it, I get this error message: "Error registering the viewer with the service. An error has occurred. Access to the path is denied." Where should I start checking for this issue?

Hello,

After updating to the latest version of Telerik Reporting, all the PDFs we export from our software have an issue where text can no longer to copied correctly out of them, instead resulting in gibberish being copied.

We have tried adjusting several options in the DeviceInfo parameter of RenderReport, (from https://docs.telerik.com/reporting/doc-output/configure-the-export-formats/pdf-device-information-settings) such as ComplianceLevel, EnableAccessibility, and FontEmbedding. None of these corrected the issue.

The version of Telerik reporting we were on (where the exports were working) was 2024_Q4_18_3_24_1218
We are now on the latest version 2025_Q3_19_2_25_813

I have attached PDFs exported from both versions.

Please help!

Good Morning,

i get empty pages in word from processing from telerik designer

Hi I am using telerik report in web forms. we have implement it is from physical file i..e report definition  is present in SQL columns. will be modified at runtime and save a file in temp path. and set in to report viewer.

in c# 
 var clientReportSource = new Telerik.ReportViewer.Html5.WebForms.ReportSource();
 clientReportSource.IdentifierType = IdentifierType.UriReportSource;
 clientReportSource.Identifier = strXml;

how it can be used in in-memory or  without using physical file as references.

Hello,

we have an existing and large reporting project which we moved from .NET Framework 4 to .net 8 now (<TargetFramework>net8.0-windows</TargetFramework>). Build the project in Visual Studio is fine and successful.

When I try to open a report of this project in the ReportDesigner by selecting the .cs file I get a dialog in which thje correct Designer und project file is shown. Pressing Finish leads to the following error which I do not understand because the TargetFramework point to a windows plattform:

Build in progressMSBuild-Version 17.14.18+a338add32 für .NET Framework
Der Buildvorgang wurde am 16.09.2025 13:43:02 gestartet.
Projekt "D:\Workspace\MainNext\Components\Report\de.ser.Reporting\de.ser.Reporting\de.ser.Reporting.csproj" auf Knoten "1" (Standardziele).
C:\Program Files\dotnet\sdk\9.0.304\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.DefaultItems.targets(142,5): error NETSDK1136: Die Zielplattform muss auf Windows festgelegt werden (üblicherweise durch Einbeziehen von "-windows" in die TargetFramework-Eigenschaft), wenn Windows Forms oder WPF verwendet wird oder auf Projekte oder Pakete verwiesen wird, die dies tun. [D:\Workspace\MainNext\Components\Report\de.ser.Reporting\de.ser.Reporting\de.ser.Reporting.csproj]
Die Erstellung des Projekts "D:\Workspace\MainNext\Components\Report\de.ser.Reporting\de.ser.Reporting\de.ser.Reporting.csproj" ist abgeschlossen (Standardziele) -- FEHLER.
Fehler beim Buildvorgang.
"D:\Workspace\MainNext\Components\Report\de.ser.Reporting\de.ser.Reporting\de.ser.Reporting.csproj" (Standardziel) (1) ->
(_CheckForInvalidWindowsDesktopTargetingConfiguration Ziel) -> 
  C:\Program Files\dotnet\sdk\9.0.304\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.DefaultItems.targets(142,5): error NETSDK1136: Die Zielplattform muss auf Windows festgelegt werden (üblicherweise durch Einbeziehen von "-windows" in die TargetFramework-Eigenschaft), wenn Windows Forms oder WPF verwendet wird oder auf Projekte oder Pakete verwiesen wird, die dies tun. [D:\Workspace\MainNext\Components\Report\de.ser.Reporting\de.ser.Reporting\de.ser.Reporting.csproj]
    0 Warnung(en)
    1 Fehler
Verstrichene Zeit 00:00:01.77

How to solve this error?

Regards,

Chris

Hi,

there probably an issue with ASPNETCORE_ENVIRONMENT for WebReportDesigner: can't apply anything than "Development".

Steps to reproduce:

Have installed Telerik_Reporting_2025_Q3_19_2_25_813.msi in order to have installed Examples.

In Examples find out

"\CSharp\.NET 8\BlazorIntegrationDemo"

in CSharp\.NET 8\BlazorIntegrationDemo\Properties\launchSettings.json
clone section CSharp.Net8.BlazorIntegrationDemo as CSharp.Net8.BlazorIntegrationDemo.Development.Test, where change

"ASPNETCORE_ENVIRONMENT": "Development" -> "ASPNETCORE_ENVIRONMENT": "Development.Test"

you should get something like:
---
    "CSharp.Net8.BlazorIntegrationDemo.Development.Test": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development.Test"
      },
      "applicationUrl": "http://localhost:57349"
    }
---

profile CSharp.Net8.BlazorIntegrationDemo still works, but when I run for profile CSharp.Net8.BlazorIntegrationDemo.Development.Test I get 
---
Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer: Warning: Unhandled exception rendering component: Could not find 'telerikReportViewerInterop.createReportViewerWidget' ('telerikReportViewerInterop' was undefined).
Error: Could not find 'telerikReportViewerInterop.createReportViewerWidget' ('telerikReportViewerInterop' was undefined).
    at http://localhost:57339/_framework/blazor.web.js:1:537
    at Array.forEach (<anonymous>)
    at l.findFunction (http://localhost:57339/_framework/blazor.web.js:1:505)
    at b (http://localhost:57339/_framework/blazor.web.js:1:5248)
    at http://localhost:57339/_framework/blazor.web.js:1:3041
    at new Promise (<anonymous>)
    at y.beginInvokeJSFromDotNet (http://localhost:57339/_framework/blazor.web.js:1:3004)
    at gn._invokeClientMethod (http://localhost:57339/_framework/blazor.web.js:1:62730)
    at gn._processIncomingData (http://localhost:57339/_framework/blazor.web.js:1:60119)
    at connection.onreceive (http://localhost:57339/_framework/blazor.web.js:1:53760)
---

I want to create a report which includes one section (likes multi-column report) and another section (like one -column report), more detail on the attached file.

After researching, I haven't found the solution yet.

So Could Telerik builds this kind of report??

Thanks!

I am trying to follow the instructions on this URL: https://www.telerik.com/aspnet-core-ui/documentation/getting-started/video-onboarding

I added the source to the Nuget settings with this URL: https://nuget.telerik.com/v3/index.json

When I go to the NuGet package manager and select the Telerik. The first time I did enter credentials but I got a 

[Telerik] Unable to load the service index for source https://nuget.telerik.com/v3/index.json.
  Response status code does not indicate success: 401 (Unauthorized).

Since then I have tried removing and re-adding the source but I always get the same error and I can't re-enter my credentials to see if that is the issue. 

How do I check if I entered my credentials wrong and How do I fix this so I have access to the telerik nuget source?

Hello Telerik team,

I’m trying to create a simple Telerik report programmatically and bind data from a custom class using an ObjectDataSource. My class has a method GetCustomers() that returns a collection of items.

Simplified setup:

var report = new Telerik.Reporting.Report();

var objectDataSource = new Telerik.Reporting.ObjectDataSource();
objectDataSource.DataSource = typeof(CustomerDetailedModel);
objectDataSource.DataMember = "GetCustomers"; // returns IEnumerable<CustomerDetailedModel>

report.DataSource = objectDataSource;

I’ve also tried leaving DataMember

unset, but I still get an error related to assembly trust or type resolution, e.g.,

“The type or namespace ‘CustomerDetailedModel’ could not be found, or the assembly is not trusted.”

I’ve tried:

• Adding the DLL via AssemblyRef.FromFile

• Placing the DLL in the application output folder

• Using AppDomain.CurrentDomain.AssemblyResolve

• Configuring assembly references in appsettings.json

Despite this, the report cannot resolve the type at runtime.

Questions:

1. How do I make ObjectDataSource resolve a CLR type from a custom assembly in a programmatically created report?

2. What is the recommended way to configure assembly references in .NET Core / .NET 8 for reports?

Any guidance or examples would be greatly appreciated.