feat(PdfReader): render white page

[HarpunDK]

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Is your feature request related to a problem? Please describe the problem.

Hi BootstrapBlazor

I'm having issues with your PdfReader. Here is my detailed report with attached video and also an attached example.

Please let me know, if you need more information.

1. After setting the content of the reader. In certain situations, the content of the pages are not showed/displayed.
   I've attached an example, showing a bit of my workflow, but this triggers the issue.
   I'm using StateHasChanged - and thought that this might cause the issue. I'm also using layers (z-index) over the PdfReader - this could also trigger the issue.

I think it's fair if you say this flow is not supported.

Let me at least try and show you the issue:

This sample repo: https://github.com/HarpunDK/BootstrapBlazorPdfReaderSample

2025-12-17_08-11-51.mp4

Please also notice the "print" button. See "Description below".

Describe the solution you'd like

The content of the pages is not displayed/rendered until you scroll or activate an action inside the reader.

This could be solved with and "Refresh" method, possible with a delay. I'm also experiencing this with a modal - when modal is displayed and content is being "lazy-binded" the pages or view stays blank.

Print-button
Another thing: The "Print"-button. Is this just a "simple" print() of the whole page - one would expect it to print only the pdf displayed inside the reader - the download is working just fine, but print is including the whole web-page. With the printer icon inside the reader - one would expect to only print the content inside the reader.

Additional context

No response

[bb-auto]

@HarpunDK Thank you for contacting us. We will give feedback later.

[HarpunDK]

I did promise feedback monday, but I had to investigate this further.

[HarpunDK]

In addition:
Upon hiding the div outside of the reader and displaying it again and setting a new document - the scroll position is not reset. The "old" state of scroll is stored.

I also updated the sample-app with this poc.
Again, I find it very fair if this is not supported - maybe it is easy to solve.

2025-12-17_08-39-15.mp4

[ArgoZhang]

@HarpunDK hi. thank you for contacting us. i had submitted a pr in your repo.

HarpunDK/BootstrapBlazorPdfReaderSample#1

the point

1. make sure pdf reader container shown
2. render pdf

BTW

1. you can set null stream to pdf

private async Task SetNullDoc()
{
    await refReaderPage.SetPdfStreamAsync(Stream.Null);
}

2. if you wana hidden the pdf reader component. we can provider a IsShow parameter. do not wrapper PdfReader set visible to false. this will cause the PDF to fail to render or render a white page.

[ArgoZhang]

@HarpunDK release 10.0.19 add IsShow parameter

<PdfReader @ref="refReaderPage"
           ShowDownload="true"
           ShowToolbar="true"
           ViewHeight="750px"
           ShowPrint="true"
           IsShow="DocumentAvailable"
/>

private async Task SetDocument()
{
    DocumentAvailable = true;
    var spinnerOption = await SwalService.ShowSpinner<Spinner>(useTimeout: true);
    //StateHasChanged();

    var assembly = Assembly.GetExecutingAssembly();
    var resourceName = "BlazorApp1.Content.6521145.pdf";

    var stream = assembly.GetManifestResourceStream(resourceName);
    if (stream != null)
    {
        await refReaderPage.SetPdfStreamAsync(stream);
        stream.Dispose();
    }
    await Task.Delay(300);
    await spinnerOption.CloseAsync();
}

now can remove StateHasChanged for improve performance

[HarpunDK]

Hi! Thank you for the update. I will look into it. Looking promising! I did try some of it and it works as intended. Will try "null" and IsShow.

What is your take on "print"? See the second video - regarding the "print".
Really is no problem - just curios if it works as intended.