1) I use a provider to file
Dim provider As SpreadsheetDocumentProvider
provider = New SpreadsheetDocumentProvider(Server.MapPath("~/rtemp/" & l_c_fexcel.Text))
RadSpreadsheet1.Provider = provider
2) User fills info as they need
3) Click on SAVE (disk icon)
4) File saved, but is corrupted
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.
In version 2025 Q2, I am getting the following error message when opening the RadGrid in design mode:
System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Web.UI.Licensing.TelerikLicense.get_CurrentHost() at Telerik.Web.UI.Licensing.TelerikLicense.get_IsLicenseValid() at Telerik.Web.UI.RadGrid.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Design.ControlDesigner.GetDesignTimeHtml()
Form controls rendered by the embedded columns (GridBoundColumn, GridDateTimeColumn, GridNumericColumn, etc.) in EditMode="Batch" do not have a label set and fail the accessibility checks.
The issue occurs when setting the Enabled property to false, which triggers a JavaScript error and causes the components to break.
Code to replicate the problem
<telerik:RadTextBox ID="RadTextBox1" runat="server" Enabled="false"></telerik:RadTextBox>
Hi
I have a RadEditor control where some toolbar functionalities are not working.
After searching for a possible reason, I used the OnClientCommandExecuting client-side event and noticed that sometimes, instead of the args with its value, I found the item of a RadTreeList control present on the page.
I tried to reproduce the issue by inserting an Editor and a TreeList on a page. I write some text in the Editor and try to change the color or background. Not always (and I can't figure out when), but sometimes the args are incorrect.
For example, if I open a node of the tree, the error is almost certain after that.
I send you an image of my javascript debugger.
I don't know what I can do, do you have any ideas?
Thanks
Michela
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.
Getting javascript error:
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!
Dear Support Team,
we are currently trying out RadPdfViewer and have found that hyperlinks in the PDFs do not work.
During my research, I found that this has now been implemented for the Kendo UI PDF viewer for Angular (https://www.telerik.com/kendo-angular-ui/components/changelogs/kendo-angular-ui#v18.5.0).
Will this also be implemented for the ASP.NET viewer, and if so, when?
Best regards
Frank
Hi Team,
I would like to request a way to insert a new record at the bottom of the InPlace Editable RadGrid so that the row would be within the RadGrid container.
Thank you!
Hi,
I am using the pdf viewer control and can't find anything on displaying the PDF document in a 2 page spread mode e.g. page 1 and 2 side by side, 3 and 4 side by side etc.
Does the control support this?
Thanks
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
The bottom part of the last page of the PDF document stays hidden. If dragged with the mouse, the Page will move and can be viewed, releasing the mouse will scroll it back as a result, hiding the bottom part.
Issue can also be observed with the following demo: https://demos.telerik.com/aspnet-ajax/pdfviewer/overview/defaultcs.aspx
I am receiving the following ADA Compliance errors, when running a page scan for WCAG 2.1 AA:
Buttons must have discernible text: button.rcbActionButton
<button class="rcbActionButton" tabindex="-1" type="button">select</button>
Form elements must have labels: input.rcbInput.radPreventDecorate
<input name="ctl00$MainContent$MyCombo" type="text" class="rcbInput radPreventDecorate rcbEmptyMessage" id="ctl00_MainContent_MyCombo_Input" value="Search..." autocomplete="off"></input>
This is the component:
EmptyMessage="Search..."
AllowCustomText="true"
MarkFirstMatch="true"
Skin="Bootstrap"
AutoPostBack="true"
SelectMethod="GetInfo"
DataValueField="Id"
DataTextField="Name"
OnSelectedIndexChanged="MyCombo_SelectedIndexChanged"
MaxHeight="250px" aria-labelledby="InfoLabel" />
Hello -
I just updated my components to 2025.1.218, and am receiving the following ADA Compliance issues on a page scan. This is to conform to WCAG 2.1 AA. The component is the Ajax telerik:RadComboBox:
Buttons must have discernible text
<button class="rcbActionButton" tabindex="-1" type="button">select</button>
Form elements must have labels
<input name="ctl00$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!