845073: Sample to show and Hide Annotations

Author: SF4524LogeshKumar

How to/Show and Hide Annotations/ShowHideAnnotations/ShowHideAnnotations.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.10.34607.79
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ShowHideAnnotations", "ShowHideAnnotations\ShowHideAnnotations.csproj", "{AEF9913F-0F38-4676-9A9F-D1042B5C30AC}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{AEF9913F-0F38-4676-9A9F-D1042B5C30AC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{AEF9913F-0F38-4676-9A9F-D1042B5C30AC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{AEF9913F-0F38-4676-9A9F-D1042B5C30AC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{AEF9913F-0F38-4676-9A9F-D1042B5C30AC}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {31245B35-82FC-4C3B-A888-4730D0AD8EE0}
+	EndGlobalSection
+EndGlobal

How to/Show and Hide Annotations/ShowHideAnnotations/ShowHideAnnotations/Pages/Error.cshtml

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+@page
+@model ErrorModel
+@{
+    ViewData["Title"] = "Error";
+}
+
+<h1 class="text-danger">Error.</h1>
+<h2 class="text-danger">An error occurred while processing your request.</h2>
+
+@if (Model.ShowRequestId)
+{
+    <p>
+        <strong>Request ID:</strong> <code>@Model.RequestId</code>
+    </p>
+}
+
+<h3>Development Mode</h3>
+<p>
+    Swapping to the <strong>Development</strong> environment displays detailed information about the error that occurred.
+</p>
+<p>
+    <strong>The Development environment shouldn't be enabled for deployed applications.</strong>
+    It can result in displaying sensitive information from exceptions to end users.
+    For local debugging, enable the <strong>Development</strong> environment by setting the <strong>ASPNETCORE_ENVIRONMENT</strong> environment variable to <strong>Development</strong>
+    and restarting the app.
+</p>

How to/Show and Hide Annotations/ShowHideAnnotations/ShowHideAnnotations/Pages/Error.cshtml.cs

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+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using System.Diagnostics;
+
+namespace PDFViewerSample.Pages
+{
+    [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
+    [IgnoreAntiforgeryToken]
+    public class ErrorModel : PageModel
+    {
+        public string? RequestId { get; set; }
+
+        public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+
+        private readonly ILogger<ErrorModel> _logger;
+
+        public ErrorModel(ILogger<ErrorModel> logger)
+        {
+            _logger = logger;
+        }
+
+        public void OnGet()
+        {
+            RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
+        }
+    }
+
+}

How to/Show and Hide Annotations/ShowHideAnnotations/ShowHideAnnotations/Pages/Index.cshtml

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+@page "{handler?}"
+@using ShowHideAnnotations.Pages
+@model IndexModel
+@{
+    ViewData["Title"] = "Home page";
+}
+
+<div class="text-center">
+    <button id="toggleBtn" onclick="toggleAnnotations()">Hide Annotations</button>
+    <ejs-pdfviewer id="pdfviewer" style="height:600px" serviceUrl="/Index" documentPath="">
+    </ejs-pdfviewer>
+</div>
+
+<script type="text/javascript">
+    var exportObject = null;
+    var annotationsVisible = true;
+
+    // Function to run when page loads
+    document.addEventListener('DOMContentLoaded', function() {
+        // Get viewer instance
+        var viewer = document.getElementById('pdfviewer').ej2_instances[0];
+
+        // Load the PDF document
+        if (viewer) {
+            viewer.documentPath="Data/Annotations.pdf";
+
+            // You can also add any initialization code here
+            console.log("PDF viewer initialized and document loading started");
+        }
+    });
+
+    function toggleAnnotations() {
+        var viewer = document.getElementById('pdfviewer').ej2_instances[0];
+
+        if (annotationsVisible) {
+            // Hide annotations by exporting and deleting them
+            viewer.exportAnnotationsAsObject().then(function(value) {
+                exportObject = value;
+
+                var count = viewer.annotationCollection.length;
+                for (var i = 0; i < count; i++) {
+                    // Always delete the first item as the collection shrinks
+                    viewer.annotationModule.deleteAnnotationById(viewer.annotationCollection[0].annotationId);
+                }
+
+                annotationsVisible = false;
+                document.getElementById('toggleBtn').textContent = 'Show Annotations';
+            });
+        } else {
+            // Restore annotations
+            if (exportObject) {
+                var exportAnnotObject = JSON.parse(exportObject);
+                viewer.importAnnotation(exportAnnotObject);
+            }
+
+            annotationsVisible = true;
+            document.getElementById('toggleBtn').textContent = 'Hide Annotations';
+        }
+    }
+</script>