Getting Started with ASP.NET Core PDF Viewer control

4 Jul 202424 minutes to read

The ASP.NET Core PDF Viewer control is used to viewing and printing PDF files in any web application. It provides the best viewing experience available with core interactions such as zooming, scrolling, text searching, text selection, and text copying. Thumbnail, bookmark, hyperlink and table of contents support provides easy navigation within and outside the PDF files.

This section briefly explains about how to integrate ASP.NET Core PDF Viewer control in your ASP.NET Core application using Visual Studio.

Prerequisites

System requirements for ASP.NET Core controls

Integrate PDF Viewer into an ASP.NET Core application

  1. Start Visual Studio and select Create a new project.
  2. In the Create a new project dialog, select ASP.NET Core Web App.
    select-aspnet-core-web-app
  3. In the Configure your new project dialog, enter Project Name and select Next.
    Set-project-name
  4. In the Additional information dialog, select .NET 6.0 (Long-term Support) and then select Create.
    Set-framework

ASP.NET Core PDF Viewer NuGet package installation

To add ASP.NET Core PDF Viewer control, the following NuGet package need to be installed in your ASP.NET Core application based on the operating system of the server you intend to host.

NOTE

A new package called the Syncfusion.EJ2.PdfViewer.AspNet.Core is introduced in the 21.1.0.35 (2023 Volume 1) release, which is a multi-targeting package. This differs from the previous approach of platform-specific packages such as “Syncfusion.EJ2.PdfViewer.AspNet.Core.Windows,” “Syncfusion.EJ2.PdfViewer.AspNet.Core.Linux,” and “Syncfusion.EJ2.PdfViewer.AspNet.Core.OSX”. With the new multi-targeting package, all of these platforms will be supported by a single package.
This simplifies the development process for developers using the Essential Studio, as they no longer need to worry about selecting the correct package for their operating system. Overall, this change should make it easier and more convenient for developers to use Essential Studio’s PDF Viewer control in their applications.

Add Syncfusion ASP.NET Core Tag Helper

Open ~/Pages/_ViewImports.cshtml file and import the Syncfusion.EJ2 TagHelper.

@addTagHelper *, Syncfusion.EJ2

Add style sheet

The theme is referred using CDN inside the <head> of ~/Pages/Shared/_Layout.cshtml file as follows,

<head>
    ...
    <!-- Syncfusion ASP.NET Core controls styles -->
    <link rel="stylesheet" href="https://cdn.syncfusion.com/ej2/27.1.48/fluent.css" />
</head>

NOTE

Checkout the Themes topic to learn different ways (CDN, NPM package, and CRG) to refer styles in ASP.NET Core application, and to have the expected appearance for Syncfusion ASP.NET Core controls.

Add script reference

Add the required scripts using CDN inside the <head> of ~/Pages/Shared/_Layout.cshtml file as follows,

<head>
    ...
    <!-- Syncfusion ASP.NET Core controls scripts -->
    <script src="https://cdn.syncfusion.com/ej2/27.1.48/dist/ej2.min.js"></script>
</head>

Register Syncfusion Script Manager

Open ~/Pages/Shared/_Layout.cshtml page and register the script manager in the ASP.NET Core application as follows.

<body>
    ....
    ....
    <!-- Syncfusion ASP.NET Core Script Manager -->
    <ejs-scripts></ejs-scripts>
</body>

NOTE

Add the script manager <ejs-script> at the end of <body>.

Add ASP.NET Core PDF Viewer control

Add the Syncfusion ASP.NET Core PDF Viewer tag helper in ~/Pages/Index.cshtml page. You can load a PDF file in the PDF Viewer by specifying the document name in the documentPath property as below.

@page "{handler?}"
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}

<div class="text-center">
    <ejs-pdfviewer id="pdfviewer" style="height:600px" serviceUrl="/Index" documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf">
    </ejs-pdfviewer>
</div>

Add the below code in the Index.cshtml.cs which is placed inside the Pages folder.

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Memory;
using Syncfusion.EJ2.PdfViewer;
using Newtonsoft.Json;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System.Reflection;
using System.Net;

namespace PDFViewerSample.Pages
{
    [IgnoreAntiforgeryToken(Order = 1001)]
    public class IndexModel : PageModel
    {

        private readonly Microsoft.AspNetCore.Hosting.IHostingEnvironment _hostingEnvironment;
        private IMemoryCache _cache;

        public IndexModel(Microsoft.AspNetCore.Hosting.IHostingEnvironment hostingEnvironment, IMemoryCache cache)
        {
            _hostingEnvironment = hostingEnvironment;
            _cache = cache;
        }

        public IActionResult OnPostLoad([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            MemoryStream stream = new MemoryStream();
            var jsonObject = JsonConverterstring(responseData);
            object jsonResult = new object();
            if (jsonObject != null && jsonObject.ContainsKey("document"))
            {
                if (bool.Parse(jsonObject["isFileName"]))
                {
                    string documentPath = GetDocumentPath(jsonObject["document"]);
                    if (!string.IsNullOrEmpty(documentPath))
                    {
                        byte[] bytes = System.IO.File.ReadAllBytes(documentPath);
                        stream = new MemoryStream(bytes);
                    }
                    else
                    {
                        string fileName = jsonObject["document"].Split(new string[] { "://" }, StringSplitOptions.None)[0];
                        if (fileName == "http" || fileName == "https")
                        {
                            WebClient WebClient = new WebClient();
                            byte[] pdfDoc = WebClient.DownloadData(jsonObject["document"]);
                            stream = new MemoryStream(pdfDoc);
                        }
                        else
                            return this.Content(jsonObject["document"] + " is not found");
                    }
                }
                else
                {
                    byte[] bytes = Convert.FromBase64String(jsonObject["document"]);
                    stream = new MemoryStream(bytes);
                }
            }
            jsonResult = pdfviewer.Load(stream, jsonObject);
            return Content(JsonConvert.SerializeObject(jsonResult));
        }

        public Dictionary<string, string> JsonConverterstring(jsonObjects results)
        {
            Dictionary<string, object> resultObjects = new Dictionary<string, object>();
            resultObjects = results.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public)
                .ToDictionary(prop => prop.Name, prop => prop.GetValue(results, null));
            var emptyObjects = (from kv in resultObjects
                                where kv.Value != null
                                select kv).ToDictionary(kv => kv.Key, kv => kv.Value);
            Dictionary<string, string> jsonResult = emptyObjects.ToDictionary(k => k.Key, k => k.Value.ToString());
            return jsonResult;
        }

        //Post action for processing the PDF documents.
        public IActionResult OnPostRenderPdfPages([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            object jsonResult = pdfviewer.GetPage(jsonObject);
            return Content(JsonConvert.SerializeObject(jsonResult));
        }

        //Post action for unloading and disposing the PDF document resources
        public IActionResult OnPostUnload([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            pdfviewer.ClearCache(jsonObject);
            return this.Content("Document cache is cleared");
        }

        //Post action for rendering the ThumbnailImages
        public IActionResult OnPostRenderThumbnailImages([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            object result = pdfviewer.GetThumbnailImages(jsonObject);
            return Content(JsonConvert.SerializeObject(result));
        }

        //Post action for processing the bookmarks from the PDF documents
        public IActionResult OnPostBookmarks([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            object jsonResult = pdfviewer.GetBookmarks(jsonObject);
            return Content(JsonConvert.SerializeObject(jsonResult));
        }

        //Post action for rendering the annotation comments
        public IActionResult OnPostRenderAnnotationComments([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            object jsonResult = pdfviewer.GetAnnotationComments(jsonObject);
            return Content(JsonConvert.SerializeObject(jsonResult));
        }

        //Post action for exporting the annotations
        public IActionResult OnPostExportAnnotations([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            string jsonResult = pdfviewer.ExportAnnotation(jsonObject);
            return Content(jsonResult);
        }

        //Post action for importing the annotations
        public IActionResult OnPostImportAnnotations([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            string jsonResult = string.Empty;
            object JsonResult;
            if (jsonObject != null && jsonObject.ContainsKey("fileName"))
            {
                string documentPath = GetDocumentPath(jsonObject["fileName"]);
                if (!string.IsNullOrEmpty(documentPath))
                {
                    jsonResult = System.IO.File.ReadAllText(documentPath);
                }
                else
                {
                    return this.Content(jsonObject["document"] + " is not found");
                }
            }
            else
            {
                string extension = Path.GetExtension(jsonObject["importedData"]);
                if (extension != ".xfdf")
                {
                    JsonResult = pdfviewer.ImportAnnotation(jsonObject);
                    return Content(JsonConvert.SerializeObject(JsonResult));
                }
                else
                {
                    string documentPath = GetDocumentPath(jsonObject["importedData"]);
                    if (!string.IsNullOrEmpty(documentPath))
                    {
                        byte[] bytes = System.IO.File.ReadAllBytes(documentPath);
                        jsonObject["importedData"] = Convert.ToBase64String(bytes);
                        JsonResult = pdfviewer.ImportAnnotation(jsonObject);
                        return Content(JsonConvert.SerializeObject(JsonResult));
                    }
                    else
                    {
                        return this.Content(jsonObject["document"] + " is not found");
                    }
                }
            }
            return Content(jsonResult);
        }

        //Post action for downloading the PDF documents
        public IActionResult OnPostDownload([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            string documentBase = pdfviewer.GetDocumentAsBase64(jsonObject);
            return Content(documentBase);
        }

        //Post action for printing the PDF documents
        public IActionResult OnPostPrintImages([FromBody] jsonObjects responseData)
        {
            PdfRenderer pdfviewer = new PdfRenderer(_cache);
            var jsonObject = JsonConverterstring(responseData);
            object pageImage = pdfviewer.GetPrintImage(jsonObject);
            return Content(JsonConvert.SerializeObject(pageImage));
        }

        //Gets the path of the PDF document
        private string GetDocumentPath(string document)
        {
            string documentPath = string.Empty;
            if (!System.IO.File.Exists(document))
            {
                string basePath = _hostingEnvironment.WebRootPath;
                string dataPath = string.Empty;
                dataPath = basePath + "/";
                if (System.IO.File.Exists(dataPath + (document)))
                    documentPath = dataPath + document;
            }
            else
            {
                documentPath = document;
            }
            return documentPath;
        }
    }

    public class jsonObjects
    {
        public string document { get; set; }
        public string password { get; set; }
        public string zoomFactor { get; set; }
        public string isFileName { get; set; }
        public string xCoordinate { get; set; }
        public string yCoordinate { get; set; }
        public string pageNumber { get; set; }
        public string documentId { get; set; }
        public string hashId { get; set; }
        public string sizeX { get; set; }
        public string sizeY { get; set; }
        public string startPage { get; set; }
        public string endPage { get; set; }
        public string stampAnnotations { get; set; }
        public string textMarkupAnnotations { get; set; }
        public string stickyNotesAnnotation { get; set; }
        public string shapeAnnotations { get; set; }
        public string measureShapeAnnotations { get; set; }
        public string action { get; set; }
        public string pageStartIndex { get; set; }
        public string pageEndIndex { get; set; }
        public string fileName { get; set; }
        public string elementId { get; set; }
        public string pdfAnnotation { get; set; }
        public string importPageList { get; set; }
        public string uniqueId { get; set; }
        public string data { get; set; }
        public string viewPortWidth { get; set; }
        public string viewPortHeight { get; set; }
        public string tilecount { get; set; }
        public bool isCompletePageSizeNotReceived { get; set; }
        public string freeTextAnnotation { get; set; }
        public string signatureData { get; set; }
        public string fieldsData { get; set; }
        public string formDesigner { get; set; }
        public string inkSignatureData { get; set; }
        public bool hideEmptyDigitalSignatureFields { get; set; }
        public bool showDigitalSignatureAppearance { get; set; }
        public bool digitalSignaturePresent { get; set; }
        public string tileXCount { get; set; }
        public string tileYCount { get; set; }
        public string digitalSignaturePageList { get; set; }
        public string annotationCollection { get; set; }
        public string annotationsPageList { get; set; }
        public string formFieldsPageList { get; set; }
        public bool isAnnotationsExist { get; set; }
        public bool isFormFieldAnnotationsExist { get; set; }
        public string documentLiveCount { get; set; }
        public string annotationDataFormat { get; set; }
	    public string importedData { get; set; }
    }
}

In the above code,

ejs-pdfviewer refers to the PDF Viewer control among the EJ components with id as “pdfviewer”.

serviceUrl is necessary to communicate with the server which also specifies the path of the controller. Here, PdfViewer is the name of the controller.

documentPath is the property needed to load a PDF file in the PDF Viewer.

Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to run the app. Then, the Syncfusion ASP.NET Core PDF Viewer control will be rendered in the default web browser.

ASP.NET Core PDF Viewer Control

NOTE

We have provided the support to dynamically change the serviceURL. So, after changing the serviceURL dynamically, you need invoke the pdfViewer.dataBind() method to update the serviceURL quickly. This will effectively change the serviceURL dynamically. Ensure that this step is performed after version 23.1.36.
function load() {
var pdfViewer = document.getElementById(‘pdfviewer’).ej2_instances[0];
pdfViewer.serviceUrl = “/Index”;
pdfViewer.documentPath = “https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf”;
pdfViewer.dataBind();
pdfViewer.load(pdfViewer.documentPath, null);
}

NOTE

View Sample in GitHub.

NOTE

When configuring the server-backed PDF viewer, it’s essential to understand that there is no need to include the pdfium.js and pdfium.wasm files. Unlike the standalone PDF viewer, which relies on these files for local rendering, the server-backed PDF viewer fetches and renders PDFs directly from the server. Consequently, you can exclude the copy command for deployment process, as they are not required to load and display PDFs in this context.

NOTE

For hosting the web service on the Linux platform, ensure to include the SkiaSharp.NativeAssets.Linux. Additionally, for AWS environments, utilize the following packages:

Amazon Web Services (AWS) NuGet package name
AWS Lambda SkiaSharp.NativeAssets.Linux
AWS Elastic Beanstalk SkiaSharp.NativeAssets.Linux.NoDependencies v2.88.6

See also