C#教程：使用IronPDF構建PDF文本內容查看器（Windows Forms）

Step 1: Create a New Windows Forms Application in Visual Studio

To begin, launch Visual Studio and click on "Create a new project." Select "Windows Forms App (.NET Framework)" or a similar .NET template from the list.

Visual Studio New Project Creation

Next, provide a name for your project (e.g., CSharpPdfTextReader) and click the Create button. This will set up a new Windows Forms Application project.

Step 2: Install the IronPDF Library

Install-Package IronPdf

Step 3: Add a RichTextBox to Your Form for Text Display

We will use a RichTextBox control to display the extracted text content from the PDF. A RichTextBox is suitable for showing formatted text, though for this tutorial, its primary role is to present the plain text extracted by IronPDF. It effectively shows the textual information without attempting to render the PDF's original visual layout.

To add a RichTextBox:

1. Open your form in the Designer view.
2. Go to the Toolbox (View > Toolbox).
3. Find RichTextBox under "Common Controls," drag it onto your form.
4. Adjust its size and position as needed. In the Properties window, you can set its Name (e.g., pdfDataRichTextBox) and set its Dock property to Fill if you want it to take up most of the form.

Adding a RichTextBox to Form1 to display extracted PDF text

Step 4: Add a Button to Select the PDF File

Add a Button control to your form. Users will click this button to open a file dialog and select a PDF file for text extraction.

1. Drag a Button from the Toolbox onto your form.
2. In the Properties window, set its Name (e.g., openBtn) and Text (e.g., "Open PDF & Display Text").

Adding a Button to Form1 to trigger PDF selection

Step 5: Add C# Code to Load PDF and Extract Text

Double-click the button you just added ("Open PDF & Display Text") to create its Click event handler in Form1.cs.

First, ensure you have the IronPDF namespace imported at the top of your Form1.cs file:

using IronPdf;
using System; // For EventArgs, Exception
using System.Windows.Forms; // For OpenFileDialog, MessageBox, DialogResult, etc.

using IronPdf;
using System; // For EventArgs, Exception
using System.Windows.Forms; // For OpenFileDialog, MessageBox, DialogResult, etc.

Imports IronPdf
Imports System ' For EventArgs, Exception
Imports System.Windows.Forms ' For OpenFileDialog, MessageBox, DialogResult, etc.

Now, implement the event handler for the button click. This code will:

1. Prompt the user to select a PDF file.
2. Use IronPDF to load the selected PDF.
3. Use IronPDF's ExtractAllText() method to get all text from the PDF.
4. Display this extracted text in the RichTextBox.

private void openBtn_Click(object sender, EventArgs e)
{
    // Create an OpenFileDialog to open PDF files
    var openFileDialog = new OpenFileDialog
    {
        Filter = "PDF files (*.pdf)|*.pdf|All files (*.*)|*.*", // Filter to show only PDFs
        Title = "Select a PDF file to extract text from" // Dialog title
    };

    // Show dialog and check if the user selected a file
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        try
        {
            // It's recommended to set your license key once at application startup.
            // License.LicenseKey = "YourIronPdfLicenseKey"; 
            // If no key is set, IronPDF runs in trial mode (watermarks on output, time limits).
            // For text extraction, the trial is fully functional for development.

            // Load the selected PDF using IronPDF
            var pdf = PdfDocument.FromFile(openFileDialog.FileName);

            // Extract all text content from the PDF using IronPDF
            string extractedText = pdf.ExtractAllText();

            // Display the extracted text in the RichTextBox
            // (Assuming your RichTextBox is named pdfDataRichTextBox, change if different)
            pdfDataRichTextBox.Text = extractedText; 
        }
        catch (Exception ex)
        {
            // Show error message if an exception occurs
            MessageBox.Show("An error occurred while processing the PDF file: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
}

private void openBtn_Click(object sender, EventArgs e)
{
    // Create an OpenFileDialog to open PDF files
    var openFileDialog = new OpenFileDialog
    {
        Filter = "PDF files (*.pdf)|*.pdf|All files (*.*)|*.*", // Filter to show only PDFs
        Title = "Select a PDF file to extract text from" // Dialog title
    };

    // Show dialog and check if the user selected a file
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        try
        {
            // It's recommended to set your license key once at application startup.
            // License.LicenseKey = "YourIronPdfLicenseKey"; 
            // If no key is set, IronPDF runs in trial mode (watermarks on output, time limits).
            // For text extraction, the trial is fully functional for development.

            // Load the selected PDF using IronPDF
            var pdf = PdfDocument.FromFile(openFileDialog.FileName);

            // Extract all text content from the PDF using IronPDF
            string extractedText = pdf.ExtractAllText();

            // Display the extracted text in the RichTextBox
            // (Assuming your RichTextBox is named pdfDataRichTextBox, change if different)
            pdfDataRichTextBox.Text = extractedText; 
        }
        catch (Exception ex)
        {
            // Show error message if an exception occurs
            MessageBox.Show("An error occurred while processing the PDF file: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
}

Private Sub openBtn_Click(ByVal sender As Object, ByVal e As EventArgs)
	' Create an OpenFileDialog to open PDF files
	Dim openFileDialog As New OpenFileDialog With {
		.Filter = "PDF files (*.pdf)|*.pdf|All files (*.*)|*.*",
		.Title = "Select a PDF file to extract text from"
	}

	' Show dialog and check if the user selected a file
	If openFileDialog.ShowDialog() = DialogResult.OK Then
		Try
			' It's recommended to set your license key once at application startup.
			' License.LicenseKey = "YourIronPdfLicenseKey"; 
			' If no key is set, IronPDF runs in trial mode (watermarks on output, time limits).
			' For text extraction, the trial is fully functional for development.

			' Load the selected PDF using IronPDF
			Dim pdf = PdfDocument.FromFile(openFileDialog.FileName)

			' Extract all text content from the PDF using IronPDF
			Dim extractedText As String = pdf.ExtractAllText()

			' Display the extracted text in the RichTextBox
			' (Assuming your RichTextBox is named pdfDataRichTextBox, change if different)
			pdfDataRichTextBox.Text = extractedText
		Catch ex As Exception
			' Show error message if an exception occurs
			MessageBox.Show("An error occurred while processing the PDF file: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
		End Try
	End If
End Sub

Code Breakdown:

• openFileDialog: A standard dialog for file selection, filtered for PDF files.
• PdfDocument.FromFile(openFileDialog.FileName): This IronPDF method loads the chosen PDF into a PdfDocument object.
• pdf.ExtractAllText(): This is the key IronPDF function for this tutorial. It reads through the entire PDF and extracts all discernible text content into a single string. This is incredibly useful for C# parse PDF text scenarios.
• pdfDataRichTextBox.Text = extractedText;: The extracted text is then assigned to the Text property of your RichTextBox (ensure the name pdfDataRichTextBox matches the name you gave your RichTextBox control).

This demonstrates how IronPDF simplifies reading PDF text in C#, allowing developers to access PDF content programmatically with minimal effort.

Step 6: Build and Run Your C# PDF Text Viewer Application

1. In Visual Studio, go to the "Build" menu and select "Build Solution."
2. Once the build is successful, press "F5" or click the "Start" button to run the application.

Your application window will appear. Click the "Open PDF & Display Text" button, select a PDF file from your computer, and click "Open."

Running the C# PDF Text Viewer Application

The RichTextBox will then display the text content extracted from the selected PDF file.

Text content extracted from the PDF and displayed in the RichTextBox

For information on visually rendering PDFs in MAUI applications (which is different from this tutorial's text extraction focus), you might explore "PDF Viewing in MAUI Tutorial".

Conclusion: Accessing PDF Text Content Made Easy with C# and IronPDF

By following these steps, you've created a C# Windows Forms application that effectively extracts and displays text content from PDF files using IronPDF. This approach is valuable when you need to programmatically access the textual information within PDFs for display, analysis, or further processing in your .NET applications.

IronPDF provides robust capabilities for C# PDF text extraction, and it's just one part of its comprehensive feature set. You can also use IronPDF for more advanced tasks like text searching within PDFs, adding annotations, printing PDF documents, PDF encryption and decryption, and editing PDF forms.

Remember, this tutorial focused on one specific use case: making PDF text accessible in a C# application. You can adapt and expand upon this foundation to meet more complex requirements.

If you're interested in exploring the full potential of IronPDF:

• Dive into the IronPDF documentation for detailed guides and examples.
• To use IronPDF in your production applications without trial limitations, a license key is required. You can purchase a license from the IronPDF website. Licenses start from $799.
• You can also evaluate the full commercial version with a free trial.