Using NLog with WPF richtextbox

Question

I have an application which has several tabs. I am trying to add logging with NLog where the output is directed to a richtextbox.

My main form is an instance of a class MyNamespace.MainWindow and its name is MainWindow1. It has a tab and in that tab I have a RichTextBox called rtbLogBox

I have imported WpfRichTextBox extension from NuGetand place this piece of code in the MainWindow class's loaded event

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        if(logger == null) logger = LogManager.GetCurrentClassLogger();

        WpfRichTextBoxTarget rtbTarget = new WpfRichTextBoxTarget
        {
            Name = "rtbLog",
            ControlName = "rtbLogBox",
            FormName = "MainWindow"
        };

        LogManager.Configuration.AddTarget(rtbTarget);


        LogManager.Configuration.AddRule(LogLevel.Info, LogLevel.Fatal, rtbTarget.Name);

        logger.Info("This");
    }

The problem is that this does not produce any outputs in the RichTextBox control.

I have an output to a file in addition to this and that target gets the log when I run the app.

Answer 1

Since the logger is created before you are changing the LogManager's configuration, you need to notify the logger of the change.

Calling LogManager.ReconfigExistingLoggers() should do the trick.

Documentation is here.