How to Build a High-Performance C# PDF Viewer in .NET (WinForms & WPF)

Choosing a UI framework is the first hurdle in desktop development.

Note: The native Apryse PDF viewer controls are built for the .NET Framework, which remains a significant part of global software systems. Many businesses still maintain these systems because of the high cost of migration and the “If it ain't broke, don’t fix it” mindset.

If your project targets modern .NET (.NET Core or .NET 5 or higher), these specific UI controls are not supported. For modern .NET desktop projects, Apryse recommends using WebViewer within a browser wrapper for the best stability and feature parity.

A professional viewer needs to be more than a static image. The Apryse SDK provides built-in tools for interactivity:

Loading very large files such as a 10,000-page document shouldn't crash your app. The Apryse viewer uses Asynchronous Rendering to keep the UI responsive. It prioritizes the pages the user is currently looking at and renders the rest in the background.

If you're building for legal, healthcare, or financial sectors, security is a hard requirement:

Learn about What "Enterprise-Grade" Means for SaaS and Software Companies: Key Characteristics.

To get started, make sure you are in a Visual Studio project targeting .NET Framework 4.5.1+.

1. Open Visual Studio and create a new Windows Forms App (.NET Framework).

2. From the Tools menu, select NuGet Package Manager. Then select Manage NuGet Packages for Solution.

3. In the NuGet Package Manager, select the Browse tab.

4. In the Search field, type Apryse, then press Enter. This will show you the various libraries that Apryse has published.

5. In the search results, select PDFTron.NetFramework.x64.

6. In the right-hand pane, check the box next to your project name (the one you created in Step 1) and make sure the latest version is selected, and click Install.

7. In the Preview Changes dialog, click Apply to add it to your project.

After it’s been added, in the Output pane, you will see that it’s Finished:

Because we installed the x64 version of the Apryse library, you must tell Visual Studio to build a 64-bit application.

Now that the SDK is installed and your architecture is set to x64, we can add the viewer to your application's main form.

The engine for this viewer is the PDFViewCtrl class. It wraps the complex rendering logic into a manageable C# control that handles all the low-level rendering, scrolling, and input handling.

Note for WPF Users: The code below is designed for our WinForms example. If you want to create a WPF App, you cannot add the PDFViewCtrl directly to the window. Instead, you must use a WindowsFormsHost and add a reference to WindowsFormsIntegration in your project.

Wrap the viewer like this:

Once the host is added to your XAML grid, you can follow the same initialization and document loading steps shown in the WinForms example below.

Now back to our example.

In a WinForms environment, you can add the viewer to a panel from the toolbox, programmatically, or to the form itself.

After you have your base project file set up, we need to add some coding to view the PDF.

1. Open Form1.cs by right-clicking it in the Solution Explorer and selecting View Code. Replace the existing code with the following snippet:

Note: In the code below, replace YourProjectNamespace with the actual name you gave your project in Step 1. You can find this name at the top of your original Form1.cs file.

Loading a document is a two-step process. First, you create a PDFDoc object (the data) and then you pass it to the PDFViewCtrl (the UI). This separation allows you to manipulate the document data independently of the display.

Note:

2. Click Start (labeled with your project name) on the Visual Studio toolbar to run the code. Your project will open and you should see your document in the PDF viewer.

We’ve just created a simple PDF viewer and loaded our sample document.

See our Simple PDF Viewer Control - PDFViewSimple sample project for more details any many options that can be added to this project.

Does this viewer work with .NET 6, 7, or 8?

No. The native PDFViewCtrl and PDFViewWPF controls are built for the .NET Framework. For modern .NET projects, you should use Apryse WebViewer, which provides a consistent experience across web and desktop.

Do I need Microsoft Word installed for the viewer to work?

No. The Apryse SDK is completely self-contained and does not require Office or any third-party PDF software.

Do I need a separate license for WPF and WinForms?

The license is generally tied to the SDK itself, not the specific UI framework you choose to wrap it in.

Can I customize the toolbar and menus?

Yes. You can build your own UI for the viewer, giving you 100% control over the user experience and branding. This sample code provides a lot of customizable elements.

Does it support dark mode?

Yes. You can programmatically set the background color of the viewer and use "Night Mode" rendering to invert colors for a better user experience in low light.

Building a native C# PDF viewer in .NET Framework gives you the best possible performance on Windows desktops. By using the Apryse Server SDK, in just a few lines of code, you’re able to bypass months of development and can focus on building the features your users actually need.

Try the Apryse Server SDK with a free trial or check out the documentation.

Contact our sales team or join the Apryse Discord community for any questions.