Last Updated: 19 Feb 2020 16:23 by ADMIN
On the Print button click, the viewer opens a File Save dialog instead of invoking the Print dialog. Observed with Edge version 79.0.309.71.
Last Updated: 22 Jan 2020 09:30 by ADMIN
Release 2020\R1
Created by: Nasi
Comments: 0
Type: Bug Report

In HTML5 Report Viewer it is possible to intercept a client request (e.g. the request to export a report to a particular export format) and modify it like this:


The malicious script will be executed when the error message for a missing export format is displayed in the viewer.

Last Updated: 13 Dec 2019 15:27 by ADMIN
When you choose the option to print the report you get the print dialog. You select page 1 and print. After that you get a dialog saying "Printing ..." and after that, it is closed but the page is never shown on the printer. I tested this on several printers, including virtual, and page never reaches any of them. If you print the entire document, the first page is printed successfully with the rest of the report.
Last Updated: 16 Jan 2020 11:54 by ADMIN

When the user confirms changing the chart type through the "Change Chart Type" dialog window, the graph designer does not get refreshed and still shows the old chart type.

Underneath the graph item is actually changed and if the report is previewed, the new graph layout will be displayed. The current workaround is to refresh the graph designer by changing one of its properties that cause full item refresh - Culture, Graph title, NoDataMessage, etc.

Last Updated: 13 Dec 2019 15:20 by ADMIN

As virtually every product with 10+ years of development, Telerik Reporting has a certain amount of legacy code that was considered immutable at the time of writing. During the refactoring of our codebase to make it compatible with .NET Standard, we introduced a few types from System.Windows.Forms namespace to substitute the ones missing in the current version of the framework. Such types are System.Windows.Forms.CheckState and System.Windows.Forms.ControlPaint. Some of these types are introduced in recent release of .NET Core 3 for Windows Forms and therefore a conflict occurs between the types in our assemblies and the ones declared in .NET Core. The error is thrown in compile-time and it is similar to the one shown below:

The type 'CheckState' exists in both 'System.Windows.Forms, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089' and 'Telerik.Reporting, Version=, Culture=neutral, PublicKeyToken=a9d7983dfcc261be'


In a future release of our product this collision will be avoided by using a dedicated enumeration for the duplicated types. A possible workaround would be to add an extern alias to the assembly reference of Telerik.Reporting. In this case all the references to Telerik.Reporting have to be edited to use the new alias, but the code that refers to the actual types from System.Windows.Forms will remain unchanged.


Here is how the Telerik.Reporting reference would look like in the application .csproj file:

    <Reference Include="Telerik.Reporting">


Using the alias means that all the types in Telerik.Reporting namespace must be accessed with this alias. Unfortunately this also applies to C#/VB report definitions - their types must also be prepended with the alias, which could require significant effort. Here is a sample code file that initializes the WinForms Report Viewer and examines the CheckState of a CheckBox control in the form:

extern alias telerikReporting;

using System;
using System.Windows.Forms;

namespace WindowsFormsCoreDemo
    public partial class MainForm : Form
        public MainForm()
            this.Load += this.Form1_Load;

        private void Form1_Load(object sender, EventArgs e)
            this.reportViewer.ReportSource = new telerikReporting::Telerik.Reporting.UriReportSource()
                Uri = "SampleReport.trdp"


        private void CheckBox_CheckedChanged(object sender, System.EventArgs e)
            if (this.checkBox.CheckState == CheckState.Checked)
Last Updated: 13 Dec 2019 15:20 by ADMIN
Release 2020\R1
Changing the Telerik Report Viewer pageMode setting through PageMode method does not work correctly
Last Updated: 18 Nov 2019 15:43 by ADMIN
An exception is thrown when trying to configure Authentication parameters in WebServiceDataSource: Response status code does not indicate success: 400 (Bad Request)
Last Updated: 13 Dec 2019 15:20 by ADMIN
When exporting a report to PDF on Linux the document looks correct. If you try to copy text from this PDF and paste it in a text editor, the text appears as random symbols, e.g. empty squares.
Last Updated: 01 Nov 2019 16:39 by ADMIN
Until now we have always passed on the Telerik Report Designer to the customer without any problems. Now the customer gets the message that this is a trial version. How do we have to pass on the Telerik Report Designer so that this hint disappears? Many thanks.
Last Updated: 01 Nov 2019 16:49 by ADMIN
In version the executable of the Standalone designer Telerik.ReportDesigner.x86.exe runs in 64bit instead of 32bit mode.
Last Updated: 04 Dec 2019 03:46 by Mohsin

running your in Chrome 77.0.3865.75, when trying to print the following error is returned:

Refused to execute script from '' because its MIME type ('image/gif') is not executable.


and nothing happens.

wasn't this fixed in your latest update?

is there a workable solution for this issue?


Last Updated: 15 Nov 2019 08:34 by ADMIN

The print functionality cannot be used in Google Chrome 77.0.3865.75 (lastest update).  The following error is displayed in the console of the browser: Resource interpreted as Document but transferred with MIME type application/pdf.

As an alternative, you can use other web browsers for printing. 

Last Updated: 01 Nov 2019 16:46 by ADMIN
We currently allow our users to save Telerik Reports parameter values so they can be scheduled for delivery or run later without the need to enter all the parameter values.

In some instances, some of the saved parameter values are not available at run time. This currently results in the parameter value to be set to Null.

For example, we have a Customer parameter that lists all existing customers and the user selects a few customers from the list and saves the report for later user. One of the saved customer is then deleted from the database. Now when the saved report is run and all the saved customer ids are passed including the customer id that is deleted from the database the Customer parameter is set to Null.

Can non-existing report parameter values be ignored and the parameter be populated with the values that do match?
Last Updated: 22 Oct 2019 11:28 by ADMIN
When a TextBox is deleted from a localized report, if a new TextBox is added, its localized value would be set to the localized value of the deleted TextBox.
Last Updated: 20 Jun 2019 13:25 by ADMIN

If during the report rendering stage, one or more of the required entities in the File storage were removed/deleted by third-party software, it will prevent the report from finishing the rendering and throws a NullRefereceException:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Reporting.Services.Engine.Document.AddClientToolTipsResource(IList toolTips)
   at Telerik.Reporting.Services.Engine.Document.FinishRendering(ReportRendererResult result)
   at Telerik.Reporting.Services.Engine.ReportEngine.RenderReportDocument(String pendingRenderingId)
   at Telerik.Reporting.Services.Engine.TaskQueue.WorkerThread.ProcessItems()
   at Telerik.Reporting.Services.Engine.TaskQueue.WorkerThread.ThreadProc()
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()]

Last Updated: 01 Nov 2019 16:47 by ADMIN

Go to page

Open search dialog.

Try to move search dialog pressing left mouse button on search dialog title.

Incorrect behavior: search dialog disappears and appears again only when you finish pressing left mouse button.

Last Updated: 19 Feb 2020 11:42 by ADMIN

Go to page

Open Search dialog.

Type "Accessories" in search field. Wait for results.

Pick last result (Accessories - page 2) from results list. (page 2 will be opened - correct)

Close search dialog and open it again (or just clear search field).

Type "Accessories" in search field again. Wait for results.

Pick last result (Accessories - page 2) from results list again.

Incorrect behavior: page 1 will be opened instead of page 2; and first result item will be highlighted as selected instead of last result item.

Also I met situation when long results list was scrolled up to top but it was unclear how to reproduce it stable.

Last Updated: 20 Jun 2019 13:23 by ADMIN

When dynamically create a new tab which contains a report viewer, only the first report is rendered correctly. The subsequent tabs with report viewers are empty.

Last Updated: 04 Oct 2019 10:14 by ADMIN
The data coming from a JsonDataSource component has null values for a date field. Using the (IsNull, ??, IIf) to check for null does not seem to work. For example: =IIF(Fields.actualWorkHrs Is NULL, "T", "F") always returns false even when there are null values in the actualWorkHrs field.
Last Updated: 22 Jan 2020 13:00 by ADMIN
Created by: James
Comments: 1
Type: Feature Request
Please add the the report viewer control to Blazor.
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