VintaSoft Twain .NET SDK - F.A.Q.

Answers to popular questions

This page contains answers to the frequently asked questions about VintaSoft Twain .NET SDK. If you have not found an answer to your technical question, please go to the technical support page. If you have not found an answer to your sales question, please go to the general sales information page.

VintaSoft Twain .NET SDK allows to control TWAIN scanner and acquire images from TWAIN scanner. Acquired images can be preprocessed with common image processing commands (invert, rotate, resize, etc) and saved to a file (PDF, TIF, JPEG, PNG, GIF, BMP) or uploaded onto HTTP(S) or FTP server.

The SDK provides a .NET API, which can be used by .NET developer in application for Windows and Linux.

The SDK provides also a JavaScript API, which can be used by Web (JavaScript) developer in web application for Windows. .NET skills are not necessary for SDK usage in a web application.

.NET developer can use the SDK in C#, VB.NET, C++ for .NET, F#, Delphi for .NET, any other programming language compatible with .NET.

Web developer can use the SDK in JavaScript and TypeScript.

The SDK consists from:
  • .NET assemblies for .NET developer
    • .NET assemblies (.dll files) for .NET 8. Files are located in "[SDK_install_path]\Bin\DotNet8\" folder.
    • .NET assemblies (.dll files) for .NET 7. Files are located in "[SDK_install_path]\Bin\DotNet7\" folder.
    • .NET assemblies (.dll files) for .NET 6. Files are located in "[SDK_install_path]\Bin\DotNet6\" folder.
    • .NET assemblies (.dll files) for .NET Framework 4+. Files are located in "[SDK_install_path]\Bin\DotNet4\" folder.
    • .NET assemblies (.dll files) for .NET Framework 3.5. Files are located in "[SDK_install_path]\Bin\DotNet3_5\" folder.
  • JavaScript API files for Web developer
    • JavaScript files (.js files) and TypeScript modules (.d.ts files). Files are located in "[SDK_install_path]\Bin\JavaScript\" folder.
    • VintaSoft Web TWAIN service. Installer for VintaSoft Web TWAIN service is located in "[SDK_install_path]\Bin\VintasoftWebTwainService\" folder.
  • SDK documentation, which contains User Guide, .NET API Reference and JavaScript API Reference. Information about documentation can be found here.
  • Source codes of demo applications for Visual Studio .NET 2010-2022 (C# and VB.NET). Files are located in "[install_path]\Examples\" folder.
  • Compiled demo applications (.exe files) for .NET Framework 3.5/4+ and .NET 6/7. Files are located in "[SDK_install_path]\Bin\" folder.

The files allowed for distribution are listed in paragraph 4.6, 4.7 and 4.8 of the License agreement.

Please read the information about the evaluation version limitations of VintaSoft Twain .NET SDK at the bottom of this page: https://www.vintasoft.com/docs/vstwain-dotnet/Licensing-Twain-Evaluation.html
User Guide for .NET developer is available here: https://www.vintasoft.com/docs/vstwain-dotnet/
.NET API Reference is available here: https://www.vintasoft.com/docs/vstwain-dotnet/Vintasoft.Twain.html
User Guide for Web developer is available here: https://www.vintasoft.com/docs/vstwain-dotnet-web/
JavaScript API Reference for Web developer is available here: https://www.vintasoft.com/docs/vstwain-dotnet-web/Vintasoft.Twain.JS.html
If you have 64-bit application, you can use 32- or 64-bit TWAIN device manager 2.x.
If you have 32-bit application, you can use 32-bit TWAIN device manager 1.x or 32-bit TWAIN device manager 2.x.
Please read about TWAIN device managers here and make sure that TWAIN device manager is installed in your system.
Please open folder "C:\Windows\twain_32\" and check if you have 32-bit TWAIN driver for your scanner.
Please open folder "C:\Windows\twain_64\" and check if you have 64-bit TWAIN driver for your scanner.

If you do not have TWAIN driver for your scanner, please install TWAIN driver to your computer.

If you want to use WIA driver for your scanner, you need to use TWAIN device manager 1.x - this is possible in 32-bit application only.
Error message means that VintaSoft JavaScript TWAIN API cannot send request to the VintaSoft Web TWAIN service.

Please do the following steps to diagnose the problem:
1. Open URL http://localhost:25319/api/VintasoftTwainApi/Status in web browser and see the result. If you will see web page with information about VintaSoft Web TWAIN service, VintaSoft Web TWAIN service is installed and running on your computer - go to step 2; otherwise, go to step 3.
2. Open your web application in web browser, open the developer console in web browser (press Ctrl+I or F12 key), select "Network" tab, reload web page in web browser (press F5 key), analyze information in "Network" tab and try to find reason of problem.
3. Open task manager (press Ctrl+Shift+Esc keys), select "Services" tab and try to find "VintasoftWebTwainService" service. If you will find the service, go to step 4; otherwise, go to step 6.
4. If "VintasoftWebTwainService" is not running, run "VintasoftWebTwainService" service, reload your web application and see the result; otherwise, go to the step 5.
5. See "Troubleshooting" section here and try to find reason of problem.
6. Open VintaSoft JavaScript TWAIN Scanning Demo, demo will suggest to download the latest version of VintaSoft Web TWAIN service. Download and install the latest version of VintaSoft Web TWAIN service to your computer. Reload your web application and see the result.
VintaSoft Web TWAIN solution consists from 2 parts:
1. VintaSoft Web TWAIN service, which provides access to the local TWAIN scanners.
2. VintaSoft TWAIN JavaScript API, which is used by web application to access VintaSoft Web TWAIN service.

Both parts have version number and both parts can work together if they have the same version number.

For solving the problem please update VintaSoft Web TWAIN service to version 14.0.1.1:
1. Uninstall VintaSoft Web TWAIN service 14.0.0.3 from your computer.
2. Open VintaSoft JavaScript TWAIN Scanning Demo, demo will suggest to download the latest version of VintaSoft Web TWAIN service.
3. Download and install the latest version of VintaSoft Web TWAIN service to your computer.
Please open folder "C:\Windows\twain_32\" and check if you have 32-bit TWAIN driver for your scanner.
Please open folder "C:\Windows\twain_64\" and check if you have 64-bit TWAIN driver for your scanner.

If you do not have TWAIN driver for your scanner, please install TWAIN driver to your computer.

If you want to use 32-bit TWAIN driver for your scanner, you need to use 32- or 64-bit version of VintaSoft Web TWAIN service and use TWAIN device manager 1.x or 2.x.
If you want to use 64-bit TWAIN driver for your scanner, you need to use 64-bit version of VintaSoft Web TWAIN service and use TWAIN device manager 2.x.
If you want to use WIA driver for your scanner, you need to use 32-bit version of VintaSoft Web TWAIN service and use TWAIN device manager 1.x

Please read how to initialize 32- or 64-bit version of VintaSoft Web TWAIN service in the "Initialization of Vintasoft Web TWAIN service" section here.

You can check usage of TWAIN device manager 1.x and 2.x in VintaSoft JavaScript TWAIN Scanning Demo - open the demo and enable/disable TWAIN device manager using "TWAIN 2 compatible" checkbox.

There are 2 ways to subscribe to the newsletter:

  • Subscribe to the newsletter of "Announcements" forums - all releases. Register yourself in VintaSoft Tech Community forums, login and click a tick "Subscribe forum" at the bottom of the forum page which is interesting for you.
  • Purchase a license and stay informed via e-mail directly from VintaSoft Support Service about all releases of licensed product during validity period of annual subscription.

Answers to the majority of questions can be found in the documentation or this web site. Please send a message to Customer Support Service to get more help.