Telerik Forums
Reporting Forum
1 answer
34 views

Hi 

I am using Telerik web reporting, and its givingan undefined isValid error on my web reporting designer.

 

Using Asp.net core, c# with front end react application

.NET SDK: Version:           9.0.304

React 18

Also getting this confgration errror from => http://localhost:{port}/api/reportdesigner/configuration

{

    "message": "An error has occurred.",
    "exceptionMessage": "Method 'CLIMessage' in type 'RuntimeInvalidLicenseStatus' from assembly 'Telerik.Reporting, Version=19.1.25.521, Culture=neutral, PublicKeyToken=a9d7983dfcc261be' does not have an implementation.",
    "exceptionType": "System.TypeLoadException",
    "stackTrace": "   at Telerik.Reporting.Common.LicenseValidator.Init()\r\n   at Telerik.Reporting.Common.LicenseValidator.CreateInstance()\r\n   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)\r\n--- End of stack trace from previous location ---\r\n   at System.Lazy`1.CreateValue()\r\n   at Telerik.Reporting.Common.LicenseValidator.get_Instance()\r\n   at Telerik.Reporting.Services.Engine.ReportEngine.GetConfiguration()\r\n   at Telerik.Reporting.Services.AspNetCore.BusinessLogic.ReportsBusinessLogic.GetConfigurationInternal(IReportServiceConfiguration reportServiceConfiguration)\r\n   at Telerik.Reporting.Services.AspNetCore.ReportsControllerBase.GetConfiguration()\r\n   at lambda_method2(Closure, Object, Object[])\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(ActionContext actionContext, IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextExceptionFilterAsync>g__Awaited|26_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)"
}
Trish
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 updated question on 08 Feb 2026
1 answer
19 views

Hello,

I have the following scenario and would like guidance on how to achieve the desired behavior.

I have a panel that contains:

  • some common elements (for example, a title and metadata textboxes), and

  • an outer list, which itself contains an inner list.

The data source has the following structure (simplified):

[
  [
    { "Text": "exampleText1", "Value": 1 },
    { "Text": "exampleText2", "Value": 2 },
    { "Text": "exampleText3", "Value": 3 }
  ],
  [
    { "Text": "exampleText21", "Value": 1 },
    { "Text": "exampleText22", "Value": 2 },
    { "Text": "exampleText23", "Value": 3 }
  ]
]

The outer list is bound to the main data source.
The inner list uses a data source binding like:

DataSource = Fields.Item

The panel that contains the lists also includes common elements (title, metadata) that should only be visible when there is data.

The issue I am facing is related to visibility:
I would like to hide the entire panel (including the common elements) when there are no elements at all in the data structure (for example, when the outer list is empty or when it does not contain any inner items).

I have already tried the following approach:

  • creating a report parameter bound to the data source,

  • attempting to evaluate a condition such as Count(Fields.Item) > 0,

  • setting the parameter to true or false based on that condition,

  • and then binding the panel’s Visible property to this parameter.

However, I was not able to make this approach work as expected.

Could you please advise on the recommended way to detect this condition and properly control the panel’s visibility in this scenario?

Thank you in advance for your help.

Best regards,
Balazs

Petar
Telerik team
 answered on 29 Jan 2026
1 answer
24 views

Hey,

I'm currently trying to use the crosstable in a new Report.
In it I have 3 Row Groups and 1 Column Group.

I now want, bigger lines when the row groups change.
So a 3pt Line when next day and a 2pt line when next "Lager".

The problem is I dont get it done as soon as I have a column group.

I tried a lot of different variatons of the example with Previous, I tried Exec.
But still not even a bit achieved what I want.

With this: Exec('value', 'group0', Fields.Ladetag) I get the value of the Ladetag of the current row group.
But to achieve what I want, I would also need the value of the Previous row of the group. 
And here I'm lost.
I cant combine Previous and Exec.
I read abous user functios but what could I pass it...





Maybe someone has an idea.

Greetings,

Benedikt

Todor
Telerik team
 answered on 26 Jan 2026
1 answer
23 views
I am trying to create a report that when I put a sub report on it, the sub report causes objects or fields to move. Researching the problem I have read a lot about margins making sure everything fits. I have done everything I can think of. My sub report width if 5.5 inches. I have made the sub report margins to zero. but still moving objects like it does no have room. I have attached a screenshot of the report in print preview mode along with my report and sub report. please tell me what's wrong, i feel it something easy
Krasimir
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Iron
 answered on 25 Jan 2026
0 answers
83 views

just need to confirm if I have to add the Telerik.Drawing.Skia package to my C# .NET Core (9.0) API to fix the error I'm getting when I test the Telerik Swagger endpoints after we deployed to AWS. The container is AWS Linux.

 

This is the error I'm seeing when I use the swagger endpoints that do not need any parameters set, like

https://reportsapi.qa.epidev.net/api/Reports/configuration
https://reportsapi.qa.epidev.net/api/Reports/clients/sessionTimeout

etc.

{
"message""An error has occurred.",
"exceptionMessage""Cannot load assembly Telerik.Drawing.Skia. Make sure it is accessible in the current application domain.",
"exceptionType""DrawingFactoryUnavailableException",
"stackTrace": null
}

Trudy
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 asked on 21 Jan 2026
1 answer
21 views

I have an old VB.NET(.NET8) winforms app which loads some resources on sign in using 

Image.FromFile("resources\\myImage.png"

This is loaded from the resources sub folder in the runtime directory - so far so good. I also allow the user to change the "focus" of the application, which loads a different image, again so far so good - all of the images are correctly found.

However, if I show the Winforms report viewer, the Directory.CurrentDirectory is reset from the correct runtime folder to the folder which contained the report (which is a UNC share)

This means that loading the images fails - it's looking in the reports directory rather than the runtime directory.

Any one have any ideas on how to solve this?

Dimitar
Telerik team
 answered on 15 Jan 2026
1 answer
36 views

I have a C#, WPF application that generates some data. I need to put that data into various Tables in a PDF file.

I'm trying to create a Table in a PDF by following this example.

I don't know if the Table is:

Telerik,Reporting.Table
or
Telerik.Reporting.Processing.Table.

Either way, I cannot get it to work.

If I use:

Telerik.Reporting.Table table = new();

the table does not have ".Rows."

If I use:

Telerik.Reporting.Processing.Table table = new();

I get the following error:

'Table' does not contain a constructor that takes 0 arguments.

Please help, I have not been able to find a way to get this to work.

Thanks,
Terry

Dess | Tech Support Engineer, Principal
Telerik team
 answered on 14 Jan 2026
1 answer
26 views
We are using 19.0.25.211 of the report viewer (we cannot go higher due to other constraints)

When using Telerik.Reporting.ReportPackager to Unpack an existing report file, we get the following error.

Could not load file or assembly 'Telerik.Reporting.Data.Design, Version=19.0.25.211

I cannot find detail on this specific assembly anywhere.

We need to Unpack the report in order to update internal datasources etc.
Ivet
Telerik team
 answered on 14 Jan 2026
1 answer
29 views
I have the following inside of a table cell:

= "From: " + IsNull(Fields.OriginalLocation, '')
+ "\r\n"
+ "To: " + IsNull(Fields.NewLocation, '')
+ "\r\n"
+ "By: " + IsNull(Fields.Person, '')
+ "\r\n"
+ "On: " + IsNull(Fields.Date, '')

This does not work inside of the web report designer's "Value" field for the table cell. I have tried other methods as well. How can I ensure that there is a new line character between each of these?
Ivet
Telerik team
 answered on 12 Jan 2026
1 answer
63 views

Due to the recent changes regarding developer licensing, I have been asked to get clarity on what is allowed regarding developer license assignment, and the resulting impact on ensuring that built files are correctly licensed.
According to "https://www.telerik.com/purchase/faq/licensing-purchasing", under "How do I assign developers and managers to the purchased licenses?", it states that "The license holder can assign license developers and managers through Your Account in the section Licensed Users and reassign them anytime."  This wording appears to suggest that developer licenses can be reassigned freely as needed, yet my understanding is that this is not the intended interpretation, and that reassignment is only permitted under specific circumstances. I have not been able to find any documentation that explicitly states this.

Our concern arises from how these licensing changes affect the building of .NET assemblies.  According to the license agreement at "https://www.telerik.com/purchase/license-agreement/reporting-dlw-s", we are granted what appears to be an unlimited testing and building license, not restricted by seat count, however the new licensing behavior seems to conflict with this. Any assembly that uses Telerik Reporting and is built by an unlicensed developer will be unlicensed at runtime.

4.A.1.1.2. Testing and Building License. If you purchase a Developer License, you may also use (as applicable based on the Product(s) identified in the Order or included in the DevTools collection(s) identified in the Order) the UI/Kendo Products Product Package, and/or Progress Telerik Reporting Product Package in the testing and building of Your Integrated Products. Testing consists of one or more of the following functions: retrieving source code developed by your Licenced Developers from the source control repository, and/or using a compiled version of Your Integrated Product, for the purposes of quality assurance (i.e. writing tests and manually testing). Building consists of one or more of the following functions: retrieving code developed by Your Licensed Developers from the source control repository, compiling such code (without making or performing any modifications, customizations, configurations, or further development actions which utilize or impact the Products) and checking dependencies and modules, running automated unit tests, linking libraries and code, building and storing artifacts, archiving build logs, and publishing/distributing Your Integrated Products to your Permitted End Users. This testing and building license is not limited to a number of seats.

Additionally, at least one cross‑reference within that license agreement appears to point to an incorrect section number (the one referring to the definition of a user points to the section adjacent to the actual definition); the rest may be worth a brief look.

If there is a page that explicitly clarifies the intended rules around developer license assignment and reassignment, I would appreciate being directed to it.  If no such clarification currently exists, I recommend including this information in the appropriate documentation, as the current wording appears ambiguous.

Thank you in advance for your guidance.

Dimitar
Telerik team
 answered on 09 Jan 2026
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