The PDF Viewer fails to display the loaded document if StateHasChanged() is called when the Data parameter is set.
A possible workaround is to call await Task.Delay(...) after StateHasChanged()
Test Page (run this in a server app):
<h1>PDF Viewer Tests</h1>
<h2>Load Initially</h2>
<TelerikPdfViewer Data="@FileData1"
EnableLoaderContainer="true"
Height="30vh"
Zoom="0.75m">
</TelerikPdfViewer>
<h2>Load On Demand</h2>
<TelerikButton ThemeColor="@ThemeConstants.Button.ThemeColor.Primary"
OnClick="@( async () => await LoadPdf(2) )">Load PDF</TelerikButton>
<TelerikPdfViewer Data="@FileData2"
EnableLoaderContainer="true"
Height="30vh"
Zoom="0.75m">
</TelerikPdfViewer>
@code {
private byte[]? FileData1 { get; set; }
private byte[]? FileData2 { get; set; }
protected async override Task OnInitializedAsync()
{
await LoadPdf(1);
}
public async Task LoadPdf(int id)
{
await Task.Delay(1000);
if (id == 2)
{
FileData2 = Convert.FromBase64String(PdfBase64);
}
else
{
FileData1 = Convert.FromBase64String(PdfBase64);
}
StateHasChanged();
await Task.Delay(300);
}
private const string PdfBase64 = "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";
}