#1236: Improve PDF password prompt cancellation handling (#1255)

Added OnDocumentLoadError callback in Blazor to hide the PDF viewer on load errors. Updated JS to detect password prompt cancellation, destroy loading task, and notify Blazor, preventing repeated prompts and improving user experience.

Author: gvreddy04

BlazorBootstrap.Demo.RCL/Components/Pages/Demos/PdfViewer/PdfViewer_Demo_05_Password_Protected_B_Prompt_For_Password.razor

@@ -1,6 +1,8 @@
 @if (showPdfViewer)
 {
-    <PdfViewer Class="mb-3" Url="@($"../{DemoStringConstants.StaticAssets_Docs_Path}/pdf_password_protected.pdf")" PromptForPassword="true" />
+    <PdfViewer Class="mb-3"
+               Url="@($"../{DemoStringConstants.StaticAssets_Docs_Path}/pdf_password_protected.pdf")"
+               OnDocumentLoadError="OnDocumentLoadError" />
 }
 else
 {
@@ -9,4 +11,6 @@ else
 
 @code {
     private bool showPdfViewer = false;
+
+    private void OnDocumentLoadError(string errorMessage) => showPdfViewer = false;
 }

blazorbootstrap/wwwroot/blazor.bootstrap.pdf.js

@@ -210,15 +210,30 @@ export function initialize(dotNetHelper, elementId, scale, rotation, url, passwo
 
     // begin loading document
     const loadingTask = pdfJS.getDocument(options);
+    let passwordPromptCanceled = false;
 
     // handle password only when required (optional password support)
     loadingTask.onPassword = function (updatePassword, reason) {
+        if (passwordPromptCanceled) return;
+
         if (reason === pdfJS.PasswordResponses.NEED_PASSWORD) {
             // only prompt if PDF actually requires password
             const password = prompt("This PDF is password protected. Enter password:");
+            if (password === null) {
+                passwordPromptCanceled = true;
+                loadingTask.destroy();
+                dotNetHelper.invokeMethodAsync('DocumentLoadError', "Password prompt canceled.");
+                return;
+            }
             updatePassword(password);
         } else if (reason === pdfJS.PasswordResponses.INCORRECT_PASSWORD) {
             const password = prompt("Incorrect password. Please try again:");
+            if (password === null) {
+                passwordPromptCanceled = true;
+                loadingTask.destroy();
+                dotNetHelper.invokeMethodAsync('DocumentLoadError', "Password prompt canceled.");
+                return;
+            }
             updatePassword(password);
         }
     };