Using TWAIN in .NET Applications

Last Updated on 2018-10-10

TWAIN Scanning C# .NET

Access TWAIN API in C# or VB.NET

Image capture applications continue to grow in importance as more and more organizations look to digitize documents over paper assets. So, more developers are embedding image capture features into their.NET application. If you’re planning to do so, first determination will be what application programming interface (API) to use for communicating with imaging devices.  For this post, we will focus on the TWAIN API to interact with scanners. We will provide a general overview on how to use TWAIN in .NET (C# or VB.NET).

What’s TWAIN?

Let’s do a quick 101 on TWAIN. TWAIN is a standard software protocol defined by the TWAIN Working Group. It is an API that regulates communication between software applications and imaging devices, such as scanner, digital cameras and capture cards (If you have an interest to know the difference between TWAIN and other scanning protocols such as WIA, ISIS, SANE, you can check Document Scanning: TWAIN, WIA, ISIS or SANE? ).

There are four key elements in TWAIN. The below image highlights these but, they are the application, source manager, data source and hardware.

Four key elements in TWAIN

How to call the TWAIN interface in .NET?

Since the .NET Framework has no built-in support for TWAIN, a developer can either code from scratch by working with the interop methods of .NET to access the TWAIN API. Alternatively, a developer can use a third party .NET wrapper class for TWAIN to save a lot of time. You pick. Coding from scratch obviously offers the opportunity to vastly customize the application. The drawback is, well, you’re coding from scratch. So, this is very time consuming especially if you consider learning curves with coming to understand the TWAIN API to truly integrate it well. It can take months. The benefits of using an SDK are also pretty obvious. While the drawback might be a nominal the time savings are not so nominal. Coding can be reduced from months to just days, even just hours.

Code from scratch

To develop the TWAIN scanning code in .NET from scratch, here are some resources that might be helpful for you.

Using a third-party .NET wrapper class for TWAIN

As mentioned, perhaps you want to complete your document scanning project in a much shorter timeframe compared to coding from scratch. Maybe you don’t have time to read through the long TWAIN Specification and write and test the TWAIN code. If this is your preference,  you can take advantage of a third party .NET TWAIN SDK.

About Dynamic .NET TWAIN

Dynamsoft’s Dynamic .NET TWAIN is a C# TWAIN wrapper. It is based on the Microsoft .NET framework, which is optimized for use in C# and VB.NET.  With Dynamic .NET TWAIN, you can basically enable an capture image application using one line of code.


Here are some highlights of the features you will find in Dynamic .NET TWAIN:

  • Compatible with TWAIN Specification 2.1 and below
  • Compatible with UVC Webcams
  • Support WinForms and WPF applications for TWAIN scanning and webcam capture
  • Customizable Scanning and Loading Process (pixel type, resolution, duplex, ADF, etc.)
  • Support BMP, JPEG, PNG, TIFF, PDF and multi-page TIFF and PDF

Try Dynamic .NET TWAIN Demo App >

Get 30-day Free Trial >

Let us know in the comments section below about your experience in creating your .NET-based image capture applications.


  1. Pingback: How to Implement a Simple Desktop Scanner or Webcam Application with .NET TWAIN SDK | Document Imaging Blog

  2. Pingback: How to access TWAIN scanners in C# .Net? | Dynamsoft Blog

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