ASP.NET Core PDF Editor
How to read, view, edit a scanned PDF file in C# ASP.NET MVC web application?

Open, read, view and edit an existing scanned PDF file in ASP.NET using C# is very simple. EdgePDF provides a simple C# demo code to accomplish the task.

• Read a scanned PDF file from server side file system
• Convert the scanned PDF file to a editable PDF document, which you can do text searching on it.
• Load the editable PDF file into EdgePDF, where you can read, view, edit PDF in web browser

How to view, edit a scanned PDF file in asp.net using C#

1. Download EdgePDF asp.net PDF viewer web control
2. Install EdgePDF demo project in IIS
3. Follow step by step tutorial

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Preparation

To run the following tutorial successfully, we need the following setup ready.

1. For ASP.NET Core web app: Setup EdgePDF



2. For ASP.NET Core MVC web app: enable PDF viewer function using EdgePDF



3. For ASP.NET (.net framework): Setup EdgePDF on IIS



4. Prepare OCR resource files. Copy all contents from downloaded package /OCR Files/Source/ to {EdgePDF demo project folder}/OCRSource/



5. A demo scanned PDF file from C:\temp\pdf-scanned-1.pdf

How to read, view, edit a scanned PDF file online in ASP.NET C#?

The following steps and C# source code will help to setup a demo project, which allows you to open, view, edit a scanned PDF file in web browser using ASP.NET C# code.

After you have completed the following guide, you can open a scanned PDF file for editing through url (a sample url http://localhost:56643/?yourtarget=pdf-scanned-1.pdf)

• For ASP.NET Core web app, open file UserCommandProcessMiddleware.cs from /DemoProjects/EdgePDF for ASP.NET Core/


• For ASP.NET (.net framework) project, open file UserCommandProcessHandler.ashx from {EdgePDF demo project}/RasterEdge_Resource_Files/


• Go to method FileProcess()
• Get target scanned PDF file id from url parameter "yourtarget"
• Create a new PDFDocument object with scanned PDF file loaded
• Get the scanned PDF file pages count
• Create a new MemoryStream object for converted editable PDF document
• Set OCR resource files location
• For each scanned PDF page, using OCR engine to convert to a editable PDF page, and save editable PDF page to a Stream object
• Combine all editable PDF pages into the new editable PDF document
• Call method REProcessControl.PageLoadFile() to load editable PDF document into EdgePDF for viewing, editing

    public override PDFWebDocument FileProcess()
    {
        HttpRequest request = this.Context.Request;

        if (!String.IsNullOrEmpty(request.QueryString["yourtarget"]))
        {
            // load file
            String docid = request.QueryString["yourtarget"];
            if (docid == null) docid = "0";
            String fileName = docid;

            PDFDocument scannedDoc = new PDFDocument(@"C:\\temp\" + docid);
            int pageCount = scannedDoc.GetPageCount();

            MemoryStream editableDoc = new MemoryStream();

            // The folder that contains OCR '.traineddata' files.
            OCRHandler.SetTrainResourcePath(@"C:\Sites\EdgePDF.Sample\OCRSource");

            MemoryStream[] streams = new MemoryStream[pageCount];
            for (int i = 0; i < scannedDoc.GetPageCount(); i++)
            {
                streams[i] = new MemoryStream();
                OCRPage page = OCRHandler.Import(scannedDoc.GetPage(i));
                page.Recognize();
                page.SaveTo(MIMEType.PDF, streams[i]);
            }
            PDFDocument.CombineDocument(streams, editableDoc);

            return REProcessControl.PageLoadFile(request, this.Manager, editableDoc, fileName);
        }
        else
        {
            Logger.Log(">>> Unknown load file mode. Load default file defined in Web.config.", LogType.DEBUG);

            // load default file. defined in Web.config
            return REProcessControl.PageLoadFile(request, this.Manager, "", LoadType.Server);
        }
    }