Summary
After editing an Excel `.xlsx` file using Telerik RadSpreadsheet and saving it via the default Save option, the saved file becomes corrupted. It no longer opens in RadSpreadsheet (throws an error) and shows a repair warning in Microsoft Excel.
Reproduction Steps
1. Upload an Excel `.xlsx` file to the `ABC` folder on the server.
2. Load the file in RadSpreadsheet via a basic viewer page.
3. Make any small edit (e.g., change a cell’s value).
4. Click the built-in Save option in the RadSpreadsheet toolbar.
5. Attempt to:
- Reopen the saved file in RadSpreadsheet → Error: Object reference not set to an instance of an object.
- Open in Excel → Warning: “We found a problem with some content in ‘filename’. Do you want us to try to recover as much as we can?”
Files Attached
- `Original.xlsx` — Before editing, opens fine in both RadSpreadsheet and Excel.
- `Modified.xlsx` — After saving via RadSpreadsheet, causes errors.
- Screenshot of:
- RadSpreadsheet error :
- Excel repair prompt
Code Snippet :
<telerik:RadSpreadsheet ID="sample" runat="server" Visible="false" style="font-size: 10px;" />
protected void Page_Load(object sender, EventArgs e)
{
string fileName = (string)Session["SelectedFileName"];
SheetLoad(fileName);
}
private void SheetLoad(string fileName)
{
try
{
string filePath = Server.MapPath("~/ABC/" + fileName);
if (!File.Exists(filePath))
{
string errorMsg = "File not found: " + filePath;
ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('File not found!');", true);
return;
}
// Load spreadsheet using Telerik document provider
sample.Provider = new SpreadsheetDocumentProvider(filePath);
sample.Visible = true;
}
catch (Exception ex)
{
string errorMsg = "Error opening file: " + ex.Message + " | File: " + fileName;
ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Error loading file!');", true);
}
}
**Observation:**
* This only happens for **some files**, especially ones that likely contain advanced Excel features.
* Other simpler files save and reload without any issue.
**Assumption:**
It seems the default save behavior of RadSpreadsheet is **not preserving some Excel structures**, leading to file corruption on save.
Dear Telerik Support. I found another bug related to this one below.
This line of code also causes the same issue.
$find("txtYear").clear();
See attached Console debug output.
It is my opinion that a hot fix needs to be done asap! The work around that Derek posted on May 23rd falls short of the bigger issue. This is a serious matter and needs to be addressed immediately.
Yes, ASP.NET Webforms is outdated, but it's still around, and I think many developers are looking at moving to a newer and more modern technology. But in some cases - including mine - it's not really possible to refactor an application that has grown for 20 years overnight. The only thing I can do is put a lot of energy into changing the CSS of the controls. Which is not always easy.
I really appreciate the functionality of the Telerik controls and think it's a shame that they don't get a visual and functional update.
In this specific case, it is about the Datepicker Control, which has a different behavior than the more modern version under .NET Core. For example, the month or year selection opens in a new DIV popup. In the more modern control, this is solved in a more elegant and modern way.
I think that this list of controls that need a “front-end pimp” can certainly be extended.
Thank you!
Hi,
many customers are asking us a more MS Word-like editor supporting true document layout features such as:
- page margins and rulers
- Headers and footers
- section breaks or document structure more similar to MS Word
- Microsoft Word-inspired UI
Many thanks,
Max
Based on Ticket ID 1683806 it was suggested to add this here. It should be fairly straight forward and would resolve issues that I have.
My Suggestion:
Why can you not just add the clientEvents to the RadEditor1.FileExplorerSettings
Something like RadEditor1.FileExplorerSettings.ClientEvents.OnClientFileOpen="somefunction"
Your response.
Thank you for your suggestion to add client events directly to RadEditor1.FileExplorerSettings. It's a thoughtful idea that could indeed enhance client-side flexibility and streamline interactions.
At present, this feature is not available. However, we encourage you to submit it as a feature request through our public feedback portal, where our product team actively reviews community input for potential inclusion in future updates.
Also, please see my ticket for a bug in the ImageManager using th URL to return the item instead of the OriginalPath. This makes my custom content provider not feasible.
Thanks!
Hello -
I just updated my components to 2025.1.218, and am receiving the following ADA Compliance issues on a page scan. This is to conform to WCAG 2.1 AA. The component is the Ajax telerik:RadComboBox:
Buttons must have discernible text
<button class="rcbActionButton" tabindex="-1" type="button">select</button>
Form elements must have labels
<input name="ctl00$MainContent$ComboBox$NewCombo" type="text" class="rcbInput radPreventDecorate rcbEmptyMessage" id="ctl00_MainContent_ComboBox_NewCombo_Input" value="Search..." autocomplete="off"></input>
Component in .ascx file:
EmptyMessage="Search..."
AllowCustomText="true"
MarkFirstMatch="true"
Skin="Bootstrap"
AutoPostBack="true"
SelectMethod="GetInfo"
DataValueField="Id"
DataTextField="Name"
OnSelectedIndexChanged="ComboBox_SelectedIndexChanged"
MaxHeight="250px" aria-labelledby="InfoLabel" />
Please advise. Thanks!
I know its a long shot, but do you have anything that resembles the attached control.
Thank you
When pasting bullet lists from Microsoft Word into the editor, extra leading spaces ( ) appear in the list items. This causes unexpected indentation and formatting issues.
Before 2025 Q1
In 2025 Q1
Upgrading Telerik UI for ASP.NET AJAX to version 2025 Q1 (2025.1.211) throw a JavaScript error:
- Uncaught TypeError: Cannot read properties of undefined (reading 'parentElement')
Steps to reproduce: Have a RadWindow with NavigateUrl set to a different page:
<telerik:RadWindow ID="RadWindow1" runat="server" RenderMode="Classic" VisibleOnPageLoad="true" NavigateUrl="Default.aspx">
</telerik:RadWindow>
Hi,
Would it possible to build in a text search filter into a Listbox?
Re: https://www.telerik.com/account/support-center/view-ticket/1677442
Re: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/listbox-client-side-filter
Alan
Business Need - User Story Terminology:
As a Telerik Support Specialist, I would like our programmers to incorporate new code which will treat hyphens as if it were a space upon ExportToPdf() so that we gracefully handle for scenarios where a very long word with a hyphen will wrap to the next line instead of overlapping other content.
I reeally would like to see the Blazor Sankey Chart component in the ASP.NET AJAX library!
Kind regards
Robert
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There is a formatting issue in the editor when the "Tab" key is pressed, triggering the editor's "InsertTab" event on text that has been modified by another user. In this event, when set_enableTrackChangesOverride(true) is enabled, the editor inserts an "a" character and misformats the text in question (as shown in the video). When set_enableTrackChangesOverride(false) is set, this error does not occur.
Note: In this scenario, we need track changes enabled so the user can accept or reject the changes made by the previous user, and set_enableTrackChangesOverride(true) so that the current user can reconcile the changes made by both User 1 and User 2 without tracking their own modifications.
Before insert Tab:
After insert Tab:
Hi,
I want to convert pptx files to PDF files. Greetings
Micha