How to Print in an ASP.NET Web Application Framework

Sometimes, web applications need to print a document as the final output. However, integrating the print function with a web application can be a real-world challenge. Many web applications use asynchronous functions, and a synchronous print function could potentially cause issues. But, there's a solution! IronPrint offers the PrintAsync function, a crucial tool for web applications. In this brief tutorial, we'll demonstrate the power of the PrintAsync function combined with ASP.NET Core. This will show you how to simulate a real-world web application that prints a document as the final output.

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First Step:
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Asynchronous PDF Printing Example

This example demonstrates how to print a PDF file asynchronously in an ASP.NET Web Application (.NET Framework) project using the PrintAsync method. By using PrintAsync, the print operation is initiated asynchronously, allowing the application to remain responsive, as opposed to blocking the thread with traditional synchronous Print methods.

Add a Print Button

In your "Index.cshtml" (or home page view), add a button that triggers an action when clicked. This button will invoke an ActionResult method in your controller. Here’s how you can implement it:

@{
    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

Index page


Implement PrintAsync in the Controller

In your HomeController, you’ll implement the PrintAsync method. This method allows the print operation to occur asynchronously, enhancing the responsiveness of the application.

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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Frequently Asked Questions

How can you print documents asynchronously in an ASP.NET web application?

You can use IronPrint's PrintAsync method to print documents asynchronously in an ASP.NET web application. This method allows the print operation to be initiated without blocking the application's main thread, maintaining responsiveness.

What are the steps to integrate a print function in an ASP.NET web application?

To integrate a print function, you should download a library like IronPrint from NuGet, import it into your class file, add a print button in your UI, implement the PrintAsync method in your controller, and verify the functionality by testing the print operation.

How does the PrintAsync method enhance printing in web applications?

The PrintAsync method enhances printing by allowing operations to occur asynchronously, which means the main application thread is not blocked during printing, thus improving the application's responsiveness and user experience.

What is the advantage of using asynchronous functions in web applications?

Asynchronous functions allow tasks to be executed without blocking the main application thread, enabling other operations to continue running smoothly and improving the overall responsiveness and performance of the application.

How do you add a print button in an ASP.NET view?

In your 'Index.cshtml' or home page view, you can add a button with an onclick event that triggers an ActionResult method in your controller, such as using location.href='@Url.Action("PrintPdf", "Home")' to initiate printing.

What challenges can arise from synchronous printing in web applications?

Synchronous printing can block the main application thread, leading to decreased responsiveness and a potential freeze of the application interface until the print operation completes.

How do you verify that a document has been printed in an ASP.NET application?

After implementing the print functionality, you should test by pressing the print button in your application and verify whether the document prints as expected, ensuring that the PrintAsync method is functioning correctly.

What is the role of the PrintPdf action method in the controller?

The PrintPdf action method in the controller initiates the print operation using the PrintAsync method, allowing the application to handle the print job without blocking the main thread, and ultimately returning a view upon completion.

Chaknith Bin
Software Engineer
Chaknith works on IronXL and IronBarcode. He has deep expertise in C# and .NET, helping improve the software and support customers. His insights from user interactions contribute to better products, documentation, and overall experience.
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