How to Convert String to Int in C# (Developer Tutorial)

Introduction

In .NET development, converting between different data types is an essential skill, especially when dealing with common types like strings and integers. One of the most frequent operations you’ll perform is converting a string variable to an integer value. Whether handling numeric strings from user inputs, files, or databases, being able to efficiently convert string variables to integers is crucial. Luckily, C# offers various methods to perform these conversions effectively, thanks to the int.Parse() and int.TryParse() methods.

On the other hand, when working with PDFs, the ability to extract and manipulate text data becomes even more important, especially when dealing with documents like invoices, reports, or forms that often contain integer strings. This is where IronPDF comes in—a powerful and easy-to-use library for working with PDFs in .NET. In this article, we’ll walk through both how to convert strings to integers in C#, and how IronPDF can help you handle PDF-related tasks within your .NET projects.

Why Convert String to Integer in C#?

String-to-integer conversions are a critical step in many applications where numerical data is provided as a string. Here are some common use cases:

• User Input Handling: When users input numbers through forms or UI elements, the data often comes in as strings. Converting these values to integers is necessary for calculations or further data manipulation.
• Data from External Sources: When reading data from files, databases, or documents like PDFs, the data is often in string format. Converting these string variables to integers allows for accurate manipulation, validation, and calculations.
• Performance and Readability: Integer operations are faster than string operations, and keeping data in its intended type makes code more readable and maintainable.
• Default Value Handling: If an input string does not contain a valid number, you'll need to provide a default value when the conversion fails, ensuring the application continues to run smoothly.

Basic Methods for Converting String to Integer in C#

There are several ways to convert a string variable to an integer value in C#. The most common approaches include the Parse method, the TryParse method, and the convert class.

Using int.Parse()

The int.Parse() method is a straightforward way to convert a string to an integer. However, it assumes that the input string is in the correct format (i.e., a valid number) and will throw a FormatException if the conversion fails.

int number = int.Parse("123");

int number = int.Parse("123");

Dim number As Integer = Integer.Parse("123")

Advantages:

• Simple and direct for valid string inputs. Disadvantages:

• Throws an exception if the string is not a valid number, which may not be ideal when processing untrusted data (such as user input or data from external files).

Using int.TryParse()

For safer conversions, TryParse method is commonly used. It attempts the conversion and returns a boolean value indicating whether the conversion was successful or not. If the conversion fails, it does not throw an exception but simply returns false. The result is stored in an out parameter.

bool success = int.TryParse("123", out int result);

bool success = int.TryParse("123", out int result);

Dim result As Integer
Dim success As Boolean = Integer.TryParse("123", result)

Here, success is a boolean value indicating whether the conversion succeeded, and number is the converted integer, stored in the out parameter.

Advantages:

• Handles invalid strings gracefully by returning false instead of throwing exceptions.

• Ideal for scenarios where you are unsure if the string is a valid number. Disadvantages:

• Requires an additional check (the boolean result) to confirm whether the conversion succeeded.

Using the Convert Class

Another way to convert a string variable into an integer value is to use the convert class. The convert class includes methods that can convert different data types, including strings to integers.

int number = Convert.ToInt32("123");

int number = Convert.ToInt32("123");

Dim number As Integer = Convert.ToInt32("123")

Advantages:

• The convert class can handle a wider range of data types beyond just strings and integers. Disadvantages:

• Like the parse method, if the string variable is not in the correct format, this method throws a FormatException.

Handling PDFs in .NET with IronPDF

When working with PDFs, you may need to extract and process any integer string embedded in the document. IronPDF simplifies PDF manipulation, allowing you to extract text and numbers seamlessly. This can be especially useful in scenarios where you need to extract and convert invoice numbers, quantities, or other important data.

IronPDF Features

IronPDF offers a comprehensive set of features for working with PDFs, including:

• PDF conversion: IronPDF can convert HTML to PDF, with its full support for modern web standards, you can be assured that IronPDF will consistently return pixel-perfect PDFs from your HTML page or content. IronPDF can also convert PDF files from other formats such as DOCX, images, RTF, and more.
• PDF Generation: With IronPDF, you can generate PDFs from URLs, ASPX files, or HTML strings.
• Security features: With IronPDF, you can always be assured that any sensitive PDF files are secure thanks to its security features. Use IronPDF to encrypt your PDF files, set passwords, and set permissions for your PDF files.
• PDF editing features: With IronPDF you can process existing PDF documents, edit them, and read PDF files with ease. IronPDF offers editing features such as adding headers and footers, stamping text and images onto the PDF pages, adding custom watermarks to the PDF, working with PDF forms, and splitting or merging PDF files.
• Integration: Seamlessly integrates with ASP.NET and MVC applications.
• PDF version support: Can support PDF version 1.2-1.7

These features make IronPDF a powerful tool for any application that requires PDF functionality, from simple reports to complex document processing systems.

Combining String-to-Int Conversion with PDF Data Extraction Using IronPDF

One of the key scenarios where string-to-integer conversion and PDF handling come together is when you need to extract numerical data from PDFs. For example, you may want to extract invoice numbers, order IDs, or quantities from a PDF document, which often come in as strings. In this next example, we will demonstrate how to extract text from a PDF using IronPDF and convert any integer strings into integer values using the TryParse method.

Example Code for Extracting Numbers from PDF Text

Using IronPDF, you can extract text from a PDF and then convert any numerical strings into integers using int.TryParse(). Here’s how:

public static void Main(string[] args)
{
    PdfDocument pdf = PdfDocument.FromFile("invoice.pdf");
    // Extract text from the PDF
    string extractedText = pdf.ExtractAllText();
    // Use regex to extract potential numbers from the text
    var matches = Regex.Matches(extractedText, @"\d+");
    if (matches.Count > 0)
    {
        Console.WriteLine("Extracted number(s) from PDF:");
        foreach (Match match in matches)
        {
            if (int.TryParse(match.Value, out int num))
            {
                Console.WriteLine(num);
            }
        }
    }
    else
    {
        Console.WriteLine("Could not find any numbers in the extracted text.");
    }
}

public static void Main(string[] args)
{
    PdfDocument pdf = PdfDocument.FromFile("invoice.pdf");
    // Extract text from the PDF
    string extractedText = pdf.ExtractAllText();
    // Use regex to extract potential numbers from the text
    var matches = Regex.Matches(extractedText, @"\d+");
    if (matches.Count > 0)
    {
        Console.WriteLine("Extracted number(s) from PDF:");
        foreach (Match match in matches)
        {
            if (int.TryParse(match.Value, out int num))
            {
                Console.WriteLine(num);
            }
        }
    }
    else
    {
        Console.WriteLine("Could not find any numbers in the extracted text.");
    }
}

Public Shared Sub Main(ByVal args() As String)
	Dim pdf As PdfDocument = PdfDocument.FromFile("invoice.pdf")
	' Extract text from the PDF
	Dim extractedText As String = pdf.ExtractAllText()
	' Use regex to extract potential numbers from the text
	Dim matches = Regex.Matches(extractedText, "\d+")
	If matches.Count > 0 Then
		Console.WriteLine("Extracted number(s) from PDF:")
		For Each match As Match In matches
			Dim num As Integer
			If Integer.TryParse(match.Value, num) Then
				Console.WriteLine(num)
			End If
		Next match
	Else
		Console.WriteLine("Could not find any numbers in the extracted text.")
	End If
End Sub

Input PDF

Console Output

In this code example, we start by loading the PDF file named "invoice.pdf" and before extracting all of the text from the document using the ExtractAllText() method. To identify potential numbers within the extracted text, the code applies a regular expression (regex) \d+, which matches sequences of digits.

The matches are stored, and if any numbers are found, they are displayed on the console. Each match is individually parsed as an integer using int.TryParse(), ensuring only valid numeric values are processed. If no numbers are found, a message is displayed stating that no numbers were extracted. This approach is useful for processing PDFs containing numeric data, such as invoices, where extracting and converting numbers is essential.

Use Cases for Converting PDF Data to Integers in Real-World Applications

Here are some scenarios where converting extracted PDF text to integers can be valuable:

• Invoice Processing: Extracting and processing invoice numbers or total amounts for automated billing systems.
• Order Tracking: Retrieving order IDs or quantities from shipping or order confirmation PDFs.
• Financial Reporting: Parsing PDFs containing financial reports or transaction logs where numerical data needs to be validated or summarized.

Conclusion

Converting strings to integers is a fundamental skill in C#, especially when working with external data sources. The int.Parse() and int.TryParse() methods provide flexible ways to handle these conversions, ensuring both simplicity and safety.

Meanwhile, IronPDF empowers .NET developers to handle complex PDF workflows with ease. Whether you’re extracting text, creating dynamic reports, or converting PDF data into usable formats, IronPDF is a valuable addition to your development toolkit.

Want to try IronPDF for yourself? Start your free trial today and experience how IronPDF can transform the way you handle PDFs in your .NET applications!