Print() Method Hangs in WPF and WinForms

Updated:June 28, 2026

When you call the synchronous Print() method in a WPF or WinForms application, the method is invoked but never completes. The call hangs indefinitely, blocking the thread and freezing the UI even when the print job itself is valid.

var printer = new IronPrint.Printer();
printer.Print("Test print"); // Hangs here

var printer = new IronPrint.Printer();
printer.Print("Test print"); // Hangs here

Dim printer As New IronPrint.Printer()
printer.Print("Test print") ' Hangs here

$vbLabelText $csharpLabel

This is expected behavior. The synchronous Print() runs on the application's UI thread, where the WPF Dispatcher and threading context conflict with IronPrint's print pipeline and block the call.

Solution

Call the asynchronous API instead of the synchronous one.

var printer = new IronPrint.Printer();
await printer.PrintAsync("Test print");

var printer = new IronPrint.Printer();
await printer.PrintAsync("Test print");

Dim printer = New IronPrint.Printer()
Await printer.PrintAsync("Test print")

$vbLabelText $csharpLabel

PrintAsync() moves the print operation off the blocking path, so the job completes and the UI stays responsive in both WPF and WinForms.

Best Practices

Update IronPrint: run the latest version to pick up the fix where available.
Prefer async APIs: reach for PrintAsync() in WPF and WinForms to avoid UI thread deadlocks.
Never block on the main thread: avoid .Result and .Wait() against an async call.
Offload long-running I/O: keep printing and other external work on background or async tasks.

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

...

Ready to Get Started?

Nuget Downloads 43,228 | Version: 2026.7 just released