In this article I will explain with an example, how to upload and display PDF files from Database inside View in ASP.Net Core Razor Pages.
The PDF File will be displayed in Browser using the PDF.js JavaScript plugin.
 
 
PDF.js plugin
The PDF file will be displayed (rendered) in Browser using PDF.js JavaScript plugin.
The following files of PDF.js JavaScript plugin will be used.
1. pdf_viewer.min.css
2. pdf.min.js
3. pdf.worker.min.js
 
 
Database
This article makes use of a table named tblFiles whose schema is defined as follows.
ASP.Net Core Razor Pages: Display PDF files from Database in View
 
Note: You can download the database table SQL by clicking the download link below.
          Download SQL file
 
 
Namespaces
You will need to import the following namespaces.
using System.IO;
using System.Data.SqlClient;
using System.Collections.Generic;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
 
 
Model
The following Model class consists of the following properties needed for inserting and populating the records of the Files from database.
public class FileModel
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string ContentType { get; set; }
    public byte[] Data { get; set; }
}
 
 
Razor PageModel (Code-Behind)
The PageModel consists of three Handler methods.
Handler method for handling GET operation
Inside this Handler method, the GetFiles method is called and the public property Files is set.
Inside the GetFiles method, the records from the tblFiles table are fetched using DataReader and generic list of FileModel class objects is populated.
Note: For details about reading Connection String from AppSettings.json, please refer my article, .Net Core: Read Connection String from AppSettings.json file.
 
Finally, the generic list of FileModel public property is returned to the Razor Page.
 
Handler method for handling POST operation for uploading Files
This Handler method gets called when a File is selected and the Upload Button is clicked, and it gets the uploaded file in the IFormFile parameter.
Note: In case the IFormFile parameter is appearing NULL, then please refer the article, ASP.Net Core: IFormFile always returns NULL.
 
The uploaded file is converted to an Array of Bytes using MemoryStream class and finally, is inserted into the database table.
After successful insert of the File, RedirectToPage is called which redirects to the IndexModel Get Handler method.
 
Handler method for sending Binary Data from Database to jQuery AJAX function
When the View Link inside the HTML Table (Grid) is clicked, then the ID of the particular PDF file is sent to this Handler method and using the File ID, the File’s binary data is fetched from the database.
Note: The following Handler method performs File display and hence the return type is set to JsonResult. For more details, please refer my article Using jQuery AJAX in ASP.Net Core Razor Pages.
 
Finally, JSON is returned back to the jQuery AJAX function.
public class IndexModel : PageModel
{
    public List<FileModel> Files { get; set; }
    private IConfiguration Configuration;
 
    public IndexModel(IConfiguration _configuration)
    {
        Configuration = _configuration;
    }
 
    public void OnGet()
    {
        this.Files = this.GetFiles();
    }
 
    public IActionResult OnPostUploadFile(IFormFile postedFile)
    {
        string fileName = Path.GetFileName(postedFile.FileName);
        string contentType = postedFile.ContentType;
        using (MemoryStream ms = new MemoryStream())
        {
            postedFile.CopyTo(ms);
            string constr = this.Configuration.GetConnectionString("MyConn");
            using (SqlConnection con = new SqlConnection(constr))
            {
                string query = "INSERT INTO tblFiles VALUES (@Name, @ContentType, @Data)";
                using (SqlCommand cmd = new SqlCommand(query))
                {
                    cmd.Connection = con;
                    cmd.Parameters.AddWithValue("@Name", fileName);
                    cmd.Parameters.AddWithValue("@ContentType", contentType);
                    cmd.Parameters.AddWithValue("@Data", ms.ToArray());
                    con.Open();
                    cmd.ExecuteNonQuery();
                    con.Close();
                }
            }
        }
 
        return RedirectToPage("Index");
    }
 
    public JsonResult OnPostGetPDF(int fileId)
    {
        byte[] bytes;
        string fileName, contentType;
        string constr = this.Configuration.GetConnectionString("MyConn");
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = "SELECT Name, Data, ContentType FROM tblFiles WHERE Id=@Id";
                cmd.Parameters.AddWithValue("@Id", fileId);
                cmd.Connection = con;
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    sdr.Read();
                    bytes = (byte[])sdr["Data"];
                    contentType = sdr["ContentType"].ToString();
                    fileName = sdr["Name"].ToString();
                }
                con.Close();
            }
        }
 
        return new JsonResult(new { FileName = fileName, ContentType = contentType, Data = bytes });
    }
 
    private List<FileModel> GetFiles()
    {
        List<FileModel> files = new List<FileModel>();
        string constr = this.Configuration.GetConnectionString("MyConn");
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT Id, Name FROM tblFiles"))
            {
                cmd.Connection = con;
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        files.Add(new FileModel
                        {
                            Id = Convert.ToInt32(sdr["Id"]),
                            Name = sdr["Name"].ToString()
                        });
                    }
                }
                con.Close();
            }
        }
        return files;
    }
}
 
 
Razor Page (HTML)
Razor HTML Page consists of an HTML Form. The Form consists of an HTML FileUpload and a Submit Button.
Uploading the File
The Submit Button has been set with the POST Handler method using the asp-page-handler attribute.
Note: In the Razor PageModel, the Handler method name is OnPostUploadFile but here it will be specified as UploadFile when calling from the Razor HTML Page.
 
When the Submit Button is clicked, the UploadFile Handler method for handling POST operation will be called.
 
Displaying the PDF Files
For displaying the files, an HTML Table is used. A loop will be executed over the Model which will generate the HTML Table rows with the File records.
 
PDF.js JavaScript Implementation
First, the JavaScript and CSS files are inherited for the PDF.js JavaScript plugin.
When the View Anchor Link is clicked, the FileId is fetched from the rel attribute and then a jQuery AJAX call is made to the GetWordDocument Handler Method.
Note: For more details on how to use jQuery AJAX for calling Handler method in ASP.Net Core Razor Pages, please refer my article Using jQuery AJAX in ASP.Net Core Razor Pages.
 
Then inside the Success event handler, the Binary Data of the PDF file is received in BASE64 string format.
The BASE64 string is converted into Byte Array using the Base64ToBytes JavaScript function and passed to the LoadPdfFromBlobfunction.
Inside the LoadPdfFromBlob function, first the count of the pages of the PDF are read and then a loop is executed and the RenderPage function is called for each PDF page.
Inside the RenderPage function, a HTML5 Canvas element is created and the PDF page is rendered on the HTML5 Canvas.
@page
@addTagHelper*, Microsoft.AspNetCore.Mvc.TagHelpers
@model Razor_Display_PDF_Database.Pages.IndexModel
@{
    Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <style type="text/css">
        body { font-family: Arial; font-size: 10pt; }
        table { border: 1px solid #ccc; border-collapse: collapse; }
        table th { background-color: #F7F7F7; color: #333; font-weight: bold; }
        table th, table td { padding: 5px; border: 1px solid #ccc; }
        #pdf_container { background: #ccc; text-align: center; display: none; padding: 5px; height: 820px; overflow: auto; }
    </style>
</head>
<body>
    <form method="post" enctype="multipart/form-data">
        <input type="file" name="postedFile" />
        <input type="submit" id="btnUpload" value="Upload" asp-page-handler="UploadFile" />
    </form>
    <hr/>
    <table id="tblFiles" cellpadding="0" cellspacing="0">
        <tr>
            <th style="width:120px">File Name</th>
            <th style="width:80px"></th>
        </tr>
        @foreach (var file in Model.Files)
        {
            <tr>
                <td>@file.Name</td>
                <td><a class="view" href="javascript:;" rel='@file.Id'>View PDF</a></td>
            </tr>
        }
    </table>
    <hr/>
    <div id="pdf_container"></div>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.6.347/pdf.min.js"></script>
    <link href="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.6.347/pdf_viewer.min.css" rel ="stylesheet" type="text/css"/>
    <script type="text/javascript">
        $(function () {
            $("[id*=tblFiles] .view").click(function () {
                var data = {};
                data.fileId = 1;
                var fileId = $(this).attr("rel");
                $.ajax({
                    type: "POST",
                    url: "/Index?handler=GetPDF",
                    beforeSend: function (xhr) {
                        xhr.setRequestHeader("XSRF-TOKEN",
                            $('input:hidden[name="__RequestVerificationToken"]').val());
                    },
                    data: { "fileId": fileId },
                    success: function (r) {
                        //Convert Base64 string to Byte Array.
                        var bytes = Base64ToBytes(r.Data);
 
                        LoadPdfFromBlob(bytes);
                    }
                });
            });
        });
 
        var pdfjsLib = window['pdfjs-dist/build/pdf'];
        pdfjsLib.GlobalWorkerOptions.workerSrc = 'https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.6.347/pdf.worker.min.js';
        var pdfDoc = null;
        var scale = 1; //Set Scale for zooming PDF.
        var resolution = 1; //Set Resolution to Adjust PDF clarity.
 
        function LoadPdfFromBlob(blob) {
            //Read PDF from BLOB.
            pdfjsLib.getDocument({ data: blob }).promise.then(function (pdfDoc_) {
                pdfDoc = pdfDoc_;
 
                //Reference the Container DIV.
                var pdf_container = document.getElementById("pdf_container");
                pdf_container.innerHTML = "";
                pdf_container.style.display = "block";
 
                //Loop and render all pages.
                for (var i = 1; i <= pdfDoc.numPages; i++) {
                    RenderPage(pdf_container, i);
                }
            });
        };
        function RenderPage(pdf_container, num) {
            pdfDoc.getPage(num).then(function (page) {
                //Create Canvas element and append to the Container DIV.
                var canvas = document.createElement('canvas');
                canvas.id = 'pdf-' + num;
                ctx = canvas.getContext('2d');
                pdf_container.appendChild(canvas);
 
                //Create and add empty DIV to add SPACE between pages.
                var spacer = document.createElement("div");
                spacer.style.height = "20px";
                pdf_container.appendChild(spacer);
 
                //Set the Canvas dimensions using ViewPort and Scale.
                var viewport = page.getViewport({ scale: scale });
                canvas.height = resolution * viewport.height;
                canvas.width = resolution * viewport.width;
 
                //Render the PDF page.
                var renderContext = {
                    canvasContext: ctx,
                    viewport: viewport,
                    transform: [resolution, 0, 0, resolution, 0, 0]
                };
 
                page.render(renderContext);
            });
        };
 
        function Base64ToBytes(base64) {
            var s = window.atob(base64);
            var bytes = new Uint8Array(s.length);
            for (var i = 0; i < s.length; i++) {
                bytes[i] = s.charCodeAt(i);
            }
            return bytes;
        };
    </script>
</body>
</html>
 
 
Screenshot
ASP.Net Core Razor Pages: Display PDF files from Database in View
 
 
Browser Compatibility

The above code has been tested in the following browsers only in versions that support HTML5.

Internet Explorer  FireFox  Chrome  Safari  Opera 

* All browser logos displayed above are property of their respective owners.

 
 
Downloads
Download Code