Is it possible to display Serilog log in the program's GUI?

Question

With the logging system Serilog is it possible to display the log in a text box, or a list view or some other GUI control; what is the mechanism to get it there?

Answer 1

Serilog provides the ILogEventSink extension point for this. You can use it to add log events to a list, or render them onto a TextWriter somewhere.

There are varying degrees of sophistication possible, depending on your needs. This one (based on ConsoleSink) should get you going:

class InMemorySink : ILogEventSink
{
    readonly ITextFormatter _textFormatter = new MessageTemplateTextFormatter("{Timestamp} [{Level}] {Message}{Exception}");

    public ConcurrentQueue<string> Events { get; } = new ConcurrentQueue<string>();

    public void Emit(LogEvent logEvent)
    {
        if (logEvent == null) throw new ArgumentNullException(nameof(logEvent));
        var renderSpace = new StringWriter();
        _textFormatter.Format(logEvent, renderSpace);
        Events.Enqueue(renderSpace.ToString());
    }
}

Then hooking it up means creating an instance:

var sink = new InMemorySink();
Log.Logger = new LoggerConfiguration()
    .WriteTo.Sink(sink)
    .CreateLogger();

Then, it's up to your app to figure out how to load sink.Events into the text box when it is shown.

Adding some code to limit the size of the queue in Emit() is a good idea.

Answer 2

You might want to check out Serilog.Sinks.RichTextBox sink which can write logs to a RichTextBox control with colors, formatting, etc. similar to what you'd expect in a Console application (you have full control of the colors through themes).

The sink was originally built for WPF applications, but can easily be used with Windows Forms application as well and there's an example in the repository that shows how to use it with Windows Forms.

Disclaimer: I'm the author of the Serilog.Sinks.RichTextBox sink.

Answer 3

You can use Serilog.Sinks.TextWriter

You can display the logs on the multi-line textbox like below;

namespace SerilogSample
{
    public partial class Form1 : Form
    {
        private StringWriter _messages;
        ILogger _logger;
        public Form1()
        {
            InitializeComponent();

            _messages = new StringWriter();
            _logger = new LoggerConfiguration()
                .WriteTo.TextWriter(_messages)
                .CreateLogger();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            _logger.Information("Clicked!");
            textBox1.Text = _messages.ToString();
        }
    }
}

The result;

Answer 4

I haven't tried it, but this package looks promising for Windows Forms:

• https://github.com/umairsyed613/Serilog.Sinks.WinForms

I also started with the accepted answer and came up with my own bare-bones Windows Forms TextBox sink:

Custom sink

    public class TextBoxSink : ILogEventSink
{
    private readonly TextBox textBox;
    private readonly LogEventLevel minLevel;
    private readonly ITextFormatter formatter;

    public TextBoxSink(
        TextBox textBox,
        LogEventLevel restrictedToMinimumLevel = LogEventLevel.Verbose,
        string outputTemplate = "{Timestamp:yyyy-MM-dd HH:mm:ss} {Level:u5}: {Message:lj}{NewLine}")
    {
        this.textBox = textBox;
        minLevel = restrictedToMinimumLevel;
        formatter = new MessageTemplateTextFormatter(outputTemplate);
    }

    public void Emit(LogEvent logEvent)
    {
        if (logEvent == null) throw new ArgumentNullException(nameof(logEvent));
        if (logEvent.Level < minLevel) return;

        var sw = new StringWriter();
        formatter.Format(logEvent, sw);

        textBox.InvokeIfRequired(() => textBox.AppendText(sw.ToString()));
    }
}

Extension method (used above to manipulate the text box from any thread; source)

public static class WinFormsControlExtensions
{
    public static void InvokeIfRequired(this Control c, MethodInvoker action)
    {
        if (c.InvokeRequired)
        {
            c.Invoke(action);
        }
        else
        {
            action();
        }
    }
}

Usage

public partial class Form1 : Form
{
    public System.Windows.Forms.TextBox LogTextBox;

    private void Form1_Shown(object sender, EventArgs e)
    {
        Logger.Log = new LoggerConfiguration()
            .WriteTo.Sink(new TextBoxSink(LogTextBox))
            .CreateLogger();
    }
}