C# 日志（對於開發者的運行原理）

// Install-Package NLog
using NLog;

public class Program
{
    // Initialize a logger instance from NLog
    private static readonly Logger logger = LogManager.GetCurrentClassLogger();

    static void Main(string[] args)
    {
        // Log various levels of messages
        logger.Info("Info message");
        logger.Warn("Warning message");
        logger.Error("Error message");
        logger.Fatal("Fatal error message");
    }
}

' Install-Package NLog
Imports NLog

Public Class Program
	' Initialize a logger instance from NLog
	Private Shared ReadOnly logger As Logger = LogManager.GetCurrentClassLogger()

	Shared Sub Main(ByVal args() As String)
		' Log various levels of messages
		logger.Info("Info message")
		logger.Warn("Warning message")
		logger.Error("Error message")
		logger.Fatal("Fatal error message")
	End Sub
End Class

// Install-Package Serilog
// Install-Package Serilog.Sinks.Console
using Serilog;

public class Program
{
    static void Main(string[] args)
    {
        // Configure Serilog to write log messages to the console
        Log.Logger = new LoggerConfiguration()
            .WriteTo.Console()
            .CreateLogger();

        // Log messages at various levels
        Log.Debug("Debug message");
        Log.Information("Info message");
        Log.Warning("Warning message");
        Log.Error("Error message");
        Log.Fatal("Fatal error message");
    }
}

' Install-Package Serilog
' Install-Package Serilog.Sinks.Console
Imports Serilog

Public Class Program
	Shared Sub Main(ByVal args() As String)
		' Configure Serilog to write log messages to the console
		Log.Logger = (New LoggerConfiguration()).WriteTo.Console().CreateLogger()

		' Log messages at various levels
		Log.Debug("Debug message")
		Log.Information("Info message")
		Log.Warning("Warning message")
		Log.Error("Error message")
		Log.Fatal("Fatal error message")
	End Sub
End Class

// Install-Package Microsoft.Extensions.Logging
using Microsoft.Extensions.Logging;

public class Program
{
    static void Main(string[] args)
    {
        // Create a logger factory with console output
        ILoggerFactory loggerFactory = LoggerFactory.Create(builder =>
        {
            builder.AddConsole(); // Add console logger
        });

        // Create a logger from the factory
        ILogger logger = loggerFactory.CreateLogger<Program>();

        // Log messages at various levels
        logger.LogDebug("Debug message");
        logger.LogInformation("Info message");
        logger.LogWarning("Warning message");
        logger.LogError("Error message");
        logger.LogCritical("Critical error message");
    }
}

' Install-Package Microsoft.Extensions.Logging
Imports Microsoft.Extensions.Logging

Public Class Program
	Shared Sub Main(ByVal args() As String)
		' Create a logger factory with console output
		Dim loggerFactory As ILoggerFactory = LoggerFactory.Create(Sub(builder)
			builder.AddConsole() ' Add console logger
		End Sub)

		' Create a logger from the factory
		Dim logger As ILogger = loggerFactory.CreateLogger(Of Program)()

		' Log messages at various levels
		logger.LogDebug("Debug message")
		logger.LogInformation("Info message")
		logger.LogWarning("Warning message")
		logger.LogError("Error message")
		logger.LogCritical("Critical error message")
	End Sub
End Class

using System;
using System.Collections.Generic;

public class LogEntry
{
    public DateTime Timestamp { get; set; }
    public string Message { get; set; }
    public LogLevel Level { get; set; }
}

public enum LogLevel
{
    Info,
    Warning,
    Error
}

public class LogService
{
    public List<LogEntry> GetLogEntries()
    {
        // Sample log entries
        var logEntries = new List<LogEntry>
        {
            new LogEntry { Timestamp = DateTime.Now, Message = "Application started.", Level = LogLevel.Info },
            new LogEntry { Timestamp = DateTime.Now, Message = "Warning: Disk space low.", Level = LogLevel.Warning },
            new LogEntry { Timestamp = DateTime.Now, Message = "Error: Database connection failed.", Level = LogLevel.Error }
        };
        return logEntries;
    }
}

Imports System
Imports System.Collections.Generic

Public Class LogEntry
	Public Property Timestamp() As DateTime
	Public Property Message() As String
	Public Property Level() As LogLevel
End Class

Public Enum LogLevel
	Info
	Warning
	[Error]
End Enum

Public Class LogService
	Public Function GetLogEntries() As List(Of LogEntry)
		' Sample log entries
		Dim logEntries = New List(Of LogEntry) From {
			New LogEntry With {
				.Timestamp = DateTime.Now,
				.Message = "Application started.",
				.Level = LogLevel.Info
			},
			New LogEntry With {
				.Timestamp = DateTime.Now,
				.Message = "Warning: Disk space low.",
				.Level = LogLevel.Warning
			},
			New LogEntry With {
				.Timestamp = DateTime.Now,
				.Message = "Error: Database connection failed.",
				.Level = LogLevel.Error
			}
		}
		Return logEntries
	End Function
End Class

using IronPdf;
using System.Collections.Generic;

public class PdfReportGenerator
{
    public void GenerateLogReport(List<LogEntry> logEntries)
    {
        var renderer = new ChromePdfRenderer();
        var htmlContent = "<h1>Log Report</h1><hr/><ul>";

        // Format log entries into an HTML list
        foreach (var entry in logEntries)
        {
            htmlContent += $"<li><strong>{entry.Timestamp}</strong> - [{entry.Level}] {entry.Message}</li>";
        }
        htmlContent += "</ul>";

        // Render the HTML content to a PDF
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);

        // Save the PDF to a file
        var outputPath = "LogReport.pdf";
        pdf.SaveAs(outputPath);
    }
}

Imports IronPdf
Imports System.Collections.Generic

Public Class PdfReportGenerator
	Public Sub GenerateLogReport(ByVal logEntries As List(Of LogEntry))
		Dim renderer = New ChromePdfRenderer()
		Dim htmlContent = "<h1>Log Report</h1><hr/><ul>"

		' Format log entries into an HTML list
		For Each entry In logEntries
			htmlContent &= $"<li><strong>{entry.Timestamp}</strong> - [{entry.Level}] {entry.Message}</li>"
		Next entry
		htmlContent &= "</ul>"

		' Render the HTML content to a PDF
		Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)

		' Save the PDF to a file
		Dim outputPath = "LogReport.pdf"
		pdf.SaveAs(outputPath)
	End Sub
End Class

class Program
{
    static void Main(string[] args)
    {
        var logService = new LogService();
        var logEntries = logService.GetLogEntries();
        var pdfGenerator = new PdfReportGenerator();
        pdfGenerator.GenerateLogReport(logEntries);
    }
}

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim logService As New LogService()
		Dim logEntries = logService.GetLogEntries()
		Dim pdfGenerator = New PdfReportGenerator()
		pdfGenerator.GenerateLogReport(logEntries)
	End Sub
End Class