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Print in an ASP.NET Framework Web App with C#

Curtis Chau
Curtis Chau
Updated:

IronPrint's PrintAsync method enables non-blocking document printing in ASP.NET web applications, preventing UI freezes while processing print requests. This asynchronous approach ensures responsive web apps can handle print operations without blocking threads.

Web applications often need document printing as final output. Integrating print functionality with web applications presents challenges, particularly when dealing with asynchronous operations. IronPrint solves this with the PrintAsync function. This tutorial demonstrates implementing PrintAsync with ASP.NET Core to create a web application that prints documents without blocking.

Before implementation, note that IronPrint provides comprehensive features including printer information retrieval and custom print settings. These capabilities make it ideal for enterprise ASP.NET applications requiring robust printing functionality.

Quickstart: Async PDF Printing with IronPrint in ASP.NET

Here's a minimal example showing IronPrint's PrintAsync API—one line in your controller starts printing without freezing your app. No boilerplate required.

Nuget IconGet started making PDFs with NuGet now:

  1. Install IronPrint with NuGet Package Manager

    PM > Install-Package IronPrint

  2. Copy and run this code snippet.

    return await IronPrint.Printer.PrintAsync("Basic.pdf");

  3. Deploy to test on your live environment

    Start using IronPrint in your project today with a free trial
    arrow pointer

Minimal Workflow (5 steps)

  1. Download a C# library for printing in web applications
  2. Import IronPrint into the class file
  3. Add a print button to trigger the method
  4. Implement PrintAsync in the controller
  5. Verify document printing on button press

How Do I Implement Asynchronous PDF Printing in ASP.NET?

This example demonstrates printing a PDF file asynchronously in an ASP.NET Web Application (.NET Framework) project using the PrintAsync method. PrintAsync initiates printing asynchronously, keeping the application responsive compared to synchronous Print methods that block threads.

The asynchronous approach is critical in web applications where multiple users might trigger print operations simultaneously. Unlike the synchronous Print method, PrintAsync ensures your application handles concurrent requests without performance degradation.

Where Should I Add the Print Button?

In your "Index.cshtml" (or home page view), add a button that triggers an action when clicked. This button invokes an ActionResult method in your controller:

@{
    ViewBag.Title = "Home Page";
}

<main>
    <section class="row" aria-labelledby="aspnetTitle">
        <h1 id="title">ASP.NET</h1>
        <p>
            <!-- Button that triggers the PrintPdf ActionResult -->
            <a class="btn btn-primary btn-md" onclick="location.href='@Url.Action("PrintPdf", "Home")'">Print PDF</a>
        </p>
    </section>
</main>
@{
    ViewBag.Title = "Home Page";
}

<main>
    <section class="row" aria-labelledby="aspnetTitle">
        <h1 id="title">ASP.NET</h1>
        <p>
            <!-- Button that triggers the PrintPdf ActionResult -->
            <a class="btn btn-primary btn-md" onclick="location.href='@Url.Action("PrintPdf", "Home")'">Print PDF</a>
        </p>
    </section>
</main>
HTML

ASP.NET application interface showing navigation menu and blue Print PDF button for generating PDFs

How Do I Configure PrintAsync in My Controller?

In your HomeController, implement the PrintAsync method. This method performs print operations asynchronously, enhancing application responsiveness. Before implementing, ensure proper license key configuration for production use.

using IronPrint;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace WebApplication4.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";
            return View();
        }

        public ActionResult Contact()
        {
            return View();
        }

        // Action method to handle the printing operation
        // This makes use of the PrintAsync method to avoid blocking the main thread
        public ActionResult PrintPdf()
        {
            // Wait for the asynchronous print operation to complete
            Printer.PrintAsync("Basic.pdf").Wait();

            // Return some view, for example, a confirmation page or the index page
            return View(); // Replace with an appropriate view
        }
    }
}
using IronPrint;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace WebApplication4.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";
            return View();
        }

        public ActionResult Contact()
        {
            return View();
        }

        // Action method to handle the printing operation
        // This makes use of the PrintAsync method to avoid blocking the main thread
        public ActionResult PrintPdf()
        {
            // Wait for the asynchronous print operation to complete
            Printer.PrintAsync("Basic.pdf").Wait();

            // Return some view, for example, a confirmation page or the index page
            return View(); // Replace with an appropriate view
        }
    }
}
Imports IronPrint
Imports System.Threading.Tasks
Imports System.Web.Mvc

Namespace WebApplication4.Controllers
	Public Class HomeController
		Inherits Controller

		Public Function Index() As ActionResult
			Return View()
		End Function

		Public Function About() As ActionResult
			ViewBag.Message = "Your application description page."
			Return View()
		End Function

		Public Function Contact() As ActionResult
			Return View()
		End Function

		' Action method to handle the printing operation
		' This makes use of the PrintAsync method to avoid blocking the main thread
		Public Function PrintPdf() As ActionResult
			' Wait for the asynchronous print operation to complete
			Printer.PrintAsync("Basic.pdf").Wait()

			' Return some view, for example, a confirmation page or the index page
			Return View() ' Replace with an appropriate view
		End Function
	End Class
End Namespace
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For advanced scenarios, implement proper async/await patterns and customize the print operation. Here's an enhanced example demonstrating error handling and custom print settings:

using IronPrint;
using System;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace WebApplication4.Controllers
{
    public class HomeController : Controller
    {
        // Async action method with proper error handling
        public async Task<ActionResult> PrintPdfAdvanced()
        {
            try
            {
                // Create custom print settings
                var printSettings = new PrintSettings
                {
                    // Select specific printer
                    PrinterName = "Microsoft Print to PDF",
                    // Set paper size
                    PaperSize = PaperSize.A4,
                    // Configure orientation
                    PaperOrientation = PaperOrientation.Portrait,
                    // Set number of copies
                    NumberOfCopies = 1,
                    // Configure DPI for high-quality output
                    Dpi = 300
                };

                // Print asynchronously with custom settings
                await Printer.PrintAsync("Basic.pdf", printSettings);

                // Log successful print operation (optional)
                System.Diagnostics.Debug.WriteLine("Document printed successfully");

                // Return success view or redirect
                TempData["PrintMessage"] = "Document sent to printer successfully!";
                return RedirectToAction("Index");
            }
            catch (Exception ex)
            {
                // Handle printing errors gracefully
                System.Diagnostics.Debug.WriteLine($"Printing error: {ex.Message}");
                TempData["ErrorMessage"] = "Unable to print document. Please try again.";
                return RedirectToAction("Index");
            }
        }
    }
}
using IronPrint;
using System;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace WebApplication4.Controllers
{
    public class HomeController : Controller
    {
        // Async action method with proper error handling
        public async Task<ActionResult> PrintPdfAdvanced()
        {
            try
            {
                // Create custom print settings
                var printSettings = new PrintSettings
                {
                    // Select specific printer
                    PrinterName = "Microsoft Print to PDF",
                    // Set paper size
                    PaperSize = PaperSize.A4,
                    // Configure orientation
                    PaperOrientation = PaperOrientation.Portrait,
                    // Set number of copies
                    NumberOfCopies = 1,
                    // Configure DPI for high-quality output
                    Dpi = 300
                };

                // Print asynchronously with custom settings
                await Printer.PrintAsync("Basic.pdf", printSettings);

                // Log successful print operation (optional)
                System.Diagnostics.Debug.WriteLine("Document printed successfully");

                // Return success view or redirect
                TempData["PrintMessage"] = "Document sent to printer successfully!";
                return RedirectToAction("Index");
            }
            catch (Exception ex)
            {
                // Handle printing errors gracefully
                System.Diagnostics.Debug.WriteLine($"Printing error: {ex.Message}");
                TempData["ErrorMessage"] = "Unable to print document. Please try again.";
                return RedirectToAction("Index");
            }
        }
    }
}
IRON VB CONVERTER ERROR developers@ironsoftware.com
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This enhanced implementation showcases concepts from the Print Settings guide, including specifying printer names, configuring paper sizes, and handling errors appropriately.

When working with printer selection in web environments, leverage the Get Printer Names functionality to dynamically populate available printer lists:

// Get list of available printers
public ActionResult GetAvailablePrinters()
{
    var printers = Printer.GetPrinterNames();
    ViewBag.PrinterList = new SelectList(printers);
    return View();
}
// Get list of available printers
public ActionResult GetAvailablePrinters()
{
    var printers = Printer.GetPrinterNames();
    ViewBag.PrinterList = new SelectList(printers);
    return View();
}
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

For scenarios requiring user interaction, consider implementing a Print with Dialog approach, though this suits desktop applications better than web environments.

Additional Considerations for Production Deployment

When deploying your ASP.NET application with IronPrint, consider these factors:

  1. License Configuration: For ASP.NET applications, configure your license key in Web.config. See the Setting License Key in Web.config guide for proper setup.

  2. Printer Access: Ensure the application pool identity has permissions to access local or network printers. The Print Your Documents documentation provides printer access requirements.

  3. Error Handling: Implement robust error handling for offline printers or inaccessible documents. For technical issues, use the Engineering Request process to resolve complex problems.

  4. Performance: For high-volume printing, implement a queue system to manage print requests efficiently. The asynchronous PrintAsync is ideal for such implementations.

For comprehensive printing capabilities, consult the API Reference for detailed documentation of all methods and properties in the IronPrint namespace.

Frequently Asked Questions

How do I implement asynchronous PDF printing in ASP.NET Framework applications?

You can implement asynchronous PDF printing using IronPrint's PrintAsync method. Simply add `return await IronPrint.Printer.PrintAsync("yourfile.pdf");` in your controller action. This non-blocking approach ensures your web application remains responsive while processing print requests, preventing UI freezes during document printing operations.

Why should I use asynchronous printing instead of synchronous printing in web applications?

Asynchronous printing with IronPrint's PrintAsync method is critical for web applications where multiple users might trigger print operations simultaneously. Unlike synchronous Print methods that block threads, PrintAsync ensures your application handles concurrent requests without performance degradation, maintaining responsiveness even under heavy load.

What are the minimal steps to add PDF printing to my ASP.NET Framework project?

The minimal workflow involves 5 steps: 1) Download IronPrint library for C#, 2) Import IronPrint into your class file, 3) Add a print button to your view, 4) Implement PrintAsync in your controller action, and 5) Verify document printing works when the button is pressed. This streamlined process requires minimal code changes.

How do I add a print button to my ASP.NET view?

In your Index.cshtml or home page view, add a button that triggers a controller action. Use HTML like ``. This button will invoke the PrintPDF ActionResult method in your Home controller when clicked.

Can I customize print settings when using asynchronous printing?

Yes, IronPrint provides comprehensive features including custom print settings and printer information retrieval. These capabilities make it ideal for enterprise ASP.NET applications requiring robust printing functionality with options to configure printer selection, page orientation, margins, and other print parameters.

Curtis Chau
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.

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