Npgsql C# .NET (Funktionsweise für Entwickler)

How to use Npgsql in C#

1. Create a new Visual Studio project.
2. Install the required library.
3. Create an object for the data provider for PostgreSQL.
4. Pass the query to the provider.
5. Close the connection and dispose of the object.

Install-Package Npgsql

Npgsql .NET Provider

Npgsql is a .NET data provider that enables C# and other .NET language developers to connect to, access, and administer PostgreSQL databases. Utilizing the features of the Entity Framework Core provider and the ADO.NET data provider for PostgreSQL, it helps developers fully utilize PostgreSQL in their applications. In this article, we are going to see more about Npgsql in detail.

Important characteristics of Npgsql are as follows:

• Compatibility and Conformance: By supporting a wide range of PostgreSQL-specific features, data types, functions, and capabilities, Npgsql guarantees conformance with PostgreSQL standards.
• High Performance: Its main goal is to optimize performance by providing effective data access and manipulation through the use of asynchronous I/O operations and other performance-boosting strategies.
• Security and Reliability: Npgsql places a high priority on security, including features like SSL encryption and PostgreSQL's secure authentication techniques, which guarantee a safe database and application connection.
• Cross-Platform Support: Its seamless architecture allows it to function in a variety of operating systems, such as Windows, Linux, and macOS, giving deployment environments flexibility.
• Entity Framework Integration: Developers can use LINQ queries and ORM (Object-Relational Mapping) approaches to communicate with PostgreSQL databases thanks to Npgsql's smooth integration with Entity Framework Core.
• One well-liked lightweight connection pooler for PostgreSQL is called pgBouncer. PostgreSQL server resources can be used more effectively because of pgBouncer's ability to manage connection pooling and serve as a proxy for client connections. PgBouncer can help with load balancing by distributing incoming connections across several PostgreSQL instances when it is configured in front of PostgreSQL servers.

In their .NET applications, developers frequently use Npgsql to create connections, run SQL queries, handle transactions, carry out CRUD tasks, and maintain database schemas. It gives programmers the ability to create reliable, scalable, high-performance apps that work well with PostgreSQL databases.

Because of its wide feature set and regular updates, Npgsql is a top choice for .NET developers who want to use the strength and reliability of PostgreSQL in their C# or .NET applications while also benefiting from a flexible and well-maintained data source.

Connecting Npgsql

Developers can connect to PostgreSQL databases, run SQL queries, carry out CRUD (Create, Read, Update, Delete) tasks, manage transactions, and more using Npgsql.

This is a basic code snippet showing how to connect to a PostgreSQL database using Npgsql:

using Npgsql;
using System;

class Program
{
    static void Main(string[] args)
    {
        // Define the connection string with placeholder values
        var connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";

        // Create a connection object using the connection string
        using var connection = new NpgsqlConnection(connectionString);

        try
        {
            // Open the connection to the PostgreSQL database
            connection.Open();
            Console.WriteLine("Connected to PostgreSQL database!");

            // Perform database operations here...
        }
        catch (Exception ex)
        {
            // Handle any exceptions that occur during connection
            Console.WriteLine($"Error: {ex.Message}");
        }
        finally
        {
            // Ensure the connection is closed
            connection.Close();
        }
    }
}

using Npgsql;
using System;

class Program
{
    static void Main(string[] args)
    {
        // Define the connection string with placeholder values
        var connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";

        // Create a connection object using the connection string
        using var connection = new NpgsqlConnection(connectionString);

        try
        {
            // Open the connection to the PostgreSQL database
            connection.Open();
            Console.WriteLine("Connected to PostgreSQL database!");

            // Perform database operations here...
        }
        catch (Exception ex)
        {
            // Handle any exceptions that occur during connection
            Console.WriteLine($"Error: {ex.Message}");
        }
        finally
        {
            // Ensure the connection is closed
            connection.Close();
        }
    }
}

Imports Npgsql
Imports System

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		' Define the connection string with placeholder values
		Dim connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb"

		' Create a connection object using the connection string
		Dim connection = New NpgsqlConnection(connectionString)

		Try
			' Open the connection to the PostgreSQL database
			connection.Open()
			Console.WriteLine("Connected to PostgreSQL database!")

			' Perform database operations here...
		Catch ex As Exception
			' Handle any exceptions that occur during connection
			Console.WriteLine($"Error: {ex.Message}")
		Finally
			' Ensure the connection is closed
			connection.Close()
		End Try
	End Sub
End Class

Replace the connection string values (Host, Username, Password, Database) with the information for your PostgreSQL server. You can use Npgsql's command execution features to run SQL commands, queries, or other database operations inside the try block.

Npgsql is a popular choice for .NET developers working with PostgreSQL because it offers an extensive range of features and ways to connect with PostgreSQL databases in C#. In your application code, always make sure to handle connections, exceptions, and other fault cases effectively.

Npgsql with IronPDF

IronPDF excels with its HTML to PDF conversion capabilities, ensuring all layouts and styles are preserved. It turns web content into PDFs, suitable for reports, invoices, and documentation. HTML files, URLs, and HTML strings can be converted to PDFs effortlessly.

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        // Create a new Chrome PDF renderer
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        // Create a new Chrome PDF renderer
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		' Create a new Chrome PDF renderer
		Dim renderer = New ChromePdfRenderer()

		' 1. Convert HTML String to PDF
		Dim htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>"
		Dim pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent)
		pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf")

		' 2. Convert HTML File to PDF
		Dim htmlFilePath = "path_to_your_html_file.html" ' Specify the path to your HTML file
		Dim pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath)
		pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf")

		' 3. Convert URL to PDF
		Dim url = "http://ironpdf.com" ' Specify the URL
		Dim pdfFromUrl = renderer.RenderUrlAsPdf(url)
		pdfFromUrl.SaveAs("URLToPDF.pdf")
	End Sub
End Class

To integrate Npgsql with IronPDF, follow these steps:

1. Install the necessary NuGet packages:

   Install-Package Npgsql
   Install-Package IronPdf

   Install-Package Npgsql
   Install-Package IronPdf

   SHELL

2. Import the required namespaces in your code:

   using Npgsql;
   using IronPdf;

   using Npgsql;
   using IronPdf;

   Imports Npgsql
   Imports IronPdf

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3. Create an Npgsql connection and retrieve data from the PostgreSQL database:

   string connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";
   string query = "SELECT * FROM mytable";
   
   using (NpgsqlConnection connection = new NpgsqlConnection(connectionString))
   {
       connection.Open();
   
       using (NpgsqlCommand command = new NpgsqlCommand(query, connection))
       {
           NpgsqlDataReader dataReader = command.ExecuteReader();
   
           if (dataReader.HasRows)
           {
               while (dataReader.Read())
               {
                   // Process each row of data here
               }
           }
   
           dataReader.Close();
       }
   
       connection.Close();
   }

   string connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";
   string query = "SELECT * FROM mytable";
   
   using (NpgsqlConnection connection = new NpgsqlConnection(connectionString))
   {
       connection.Open();
   
       using (NpgsqlCommand command = new NpgsqlCommand(query, connection))
       {
           NpgsqlDataReader dataReader = command.ExecuteReader();
   
           if (dataReader.HasRows)
           {
               while (dataReader.Read())
               {
                   // Process each row of data here
               }
           }
   
           dataReader.Close();
       }
   
       connection.Close();
   }

   Dim connectionString As String = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb"
   Dim query As String = "SELECT * FROM mytable"
   
   Using connection As New NpgsqlConnection(connectionString)
   	connection.Open()
   
   	Using command As New NpgsqlCommand(query, connection)
   		Dim dataReader As NpgsqlDataReader = command.ExecuteReader()
   
   		If dataReader.HasRows Then
   			Do While dataReader.Read()
   				' Process each row of data here
   			Loop
   		End If
   
   		dataReader.Close()
   	End Using
   
   	connection.Close()
   End Using

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4. Use IronPDF to generate PDF documents based on the retrieved data:

   HtmlToPdf Renderer = new HtmlToPdf();
   HtmlDocument Html = new HtmlDocument("<html><body><h1>My Data</h1></body></html>");
   
   PdfDocument PDF = Renderer.RenderHtmlAsPdf(Html);
   
   PDF.SaveAs("result.pdf");

   HtmlToPdf Renderer = new HtmlToPdf();
   HtmlDocument Html = new HtmlDocument("<html><body><h1>My Data</h1></body></html>");
   
   PdfDocument PDF = Renderer.RenderHtmlAsPdf(Html);
   
   PDF.SaveAs("result.pdf");

   Dim Renderer As New HtmlToPdf()
   Dim Html As New HtmlDocument("<html><body><h1>My Data</h1></body></html>")
   
   Dim PDF As PdfDocument = Renderer.RenderHtmlAsPdf(Html)
   
   PDF.SaveAs("result.pdf")

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Note that you may need to customize the code according to your specific requirements and database schema.

By following these steps, you can combine the power of Npgsql and IronPDF to retrieve data from a PostgreSQL database and generate PDF documents based on that data.

Install IronPDF Library

Install-Package IronPdf

using IronPdf;
using Npgsql;
using System;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        StringBuilder sb = new StringBuilder();
        var connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";

        // Connecting to PostgreSQL using Npgsql
        await using var connection = new NpgsqlConnection(connectionString);
        try
        {
            await connection.OpenAsync();
            Console.WriteLine("Connected to PostgreSQL!");

            // Execute a database query using Npgsql
            await using var cmd = new NpgsqlCommand("SELECT username FROM my_table WHERE userid='005'", connection);
            await using var reader = await cmd.ExecuteReaderAsync();

            while (await reader.ReadAsync())
            {
                // Process database query results
                sb.Append(reader.GetString(0));
            }

            // Generate a PDF document using IronPDF
            var Renderer = new IronPdf.HtmlToPdf();
            var PDF = Renderer.RenderHtmlAsPdf($"<h1>Hello, {sb.ToString()}</h1>");
            PDF.SaveAs("Output.pdf");

            Console.WriteLine("PDF generated successfully.");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
        finally
        {
            connection.Close();
        }
    }
}

using IronPdf;
using Npgsql;
using System;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        StringBuilder sb = new StringBuilder();
        var connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb";

        // Connecting to PostgreSQL using Npgsql
        await using var connection = new NpgsqlConnection(connectionString);
        try
        {
            await connection.OpenAsync();
            Console.WriteLine("Connected to PostgreSQL!");

            // Execute a database query using Npgsql
            await using var cmd = new NpgsqlCommand("SELECT username FROM my_table WHERE userid='005'", connection);
            await using var reader = await cmd.ExecuteReaderAsync();

            while (await reader.ReadAsync())
            {
                // Process database query results
                sb.Append(reader.GetString(0));
            }

            // Generate a PDF document using IronPDF
            var Renderer = new IronPdf.HtmlToPdf();
            var PDF = Renderer.RenderHtmlAsPdf($"<h1>Hello, {sb.ToString()}</h1>");
            PDF.SaveAs("Output.pdf");

            Console.WriteLine("PDF generated successfully.");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
        finally
        {
            connection.Close();
        }
    }
}

Imports IronPdf
Imports Npgsql
Imports System
Imports System.Text
Imports System.Threading.Tasks

Friend Class Program
	Shared Async Function Main(ByVal args() As String) As Task
		Dim sb As New StringBuilder()
		Dim connectionString = "Host=myhost;Username=myuser;Password=mypassword;Database=mydb"

		' Connecting to PostgreSQL using Npgsql
		Await var connection = New NpgsqlConnection(connectionString)
		Try
			Await connection.OpenAsync()
			Console.WriteLine("Connected to PostgreSQL!")

			' Execute a database query using Npgsql
			Await var cmd = New NpgsqlCommand("SELECT username FROM my_table WHERE userid='005'", connection)
			Await var reader = Await cmd.ExecuteReaderAsync()

			Do While Await reader.ReadAsync()
				' Process database query results
				sb.Append(reader.GetString(0))
			Loop

			' Generate a PDF document using IronPDF
			Dim Renderer = New IronPdf.HtmlToPdf()
			Dim PDF = Renderer.RenderHtmlAsPdf($"<h1>Hello, {sb.ToString()}</h1>")
			PDF.SaveAs("Output.pdf")

			Console.WriteLine("PDF generated successfully.")
		Catch ex As Exception
			Console.WriteLine($"Error: {ex.Message}")
		Finally
			connection.Close()
		End Try
	End Function
End Class

Conclusion

Although there is no direct connection or dependency between Npgsql and IronPDF, developers often use both tools in the same application environment. For example, a C# program can utilize Npgsql to handle database operations, such as retrieving data from a PostgreSQL database, and then use IronPDF to generate PDF documents or reports based on the retrieved data.

By leveraging the flexibility and capabilities provided by Npgsql and IronPDF, developers can build feature-rich applications that seamlessly integrate data handling with PostgreSQL databases and dynamic PDF generation for various reporting, document management, and presentation needs.

The Lite bundle of IronPDF includes a perpetual license, upgrade options, a year of software maintenance, and a thirty-day money-back guarantee. During the trial period, users can evaluate the product in real-world application scenarios with a watermark. For more information about the cost, licensing, and trial version of IronPDF, visit the IronPDF licensing page. To learn more about Iron Software, please visit their official website.