Question

How can I use RichTextBox Target in WPF application?
I don’t want to have a separate window with log, I want all log messages to be outputted in richTextBox located in WPF dialog.

I’ve tried to use WindowsFormsHost with RichTextBox box inside but that does not worked for me: NLog opened separate Windows Form anyway.

Answer 1

If you define a RichTextBoxTarget in the config file, a new form is automatically created. This is because NLog initializes before your (named) form and control has been created. Even if you haven’t got any rules pointing to the target. Perhaps there is a better solution, but I solved it by creating the target programatically:

using NLog;
//[...]
RichTextBoxTarget target = new RichTextBoxTarget();
target.Name = "RichTextBox";
target.Layout = "${longdate} ${level:uppercase=true} ${logger} ${message}";
target.ControlName = "textbox1";
target.FormName = "Form1";
target.AutoScroll = true;
target.MaxLines = 10000;
target.UseDefaultRowColoringRules = false;
target.RowColoringRules.Add(
    new RichTextBoxRowColoringRule(
        "level == LogLevel.Trace", // condition
        "DarkGray", // font color
        "Control", // background color
        FontStyle.Regular
    )
);
target.RowColoringRules.Add(new RichTextBoxRowColoringRule("level == LogLevel.Debug", "Gray", "Control"));
target.RowColoringRules.Add(new RichTextBoxRowColoringRule("level == LogLevel.Info", "ControlText", "Control"));
target.RowColoringRules.Add(new RichTextBoxRowColoringRule("level == LogLevel.Warn", "DarkRed", "Control"));
target.RowColoringRules.Add(new RichTextBoxRowColoringRule("level == LogLevel.Error", "White", "DarkRed", FontStyle.Bold));
target.RowColoringRules.Add(new RichTextBoxRowColoringRule("level == LogLevel.Fatal", "Yellow", "DarkRed", FontStyle.Bold));

AsyncTargetWrapper asyncWrapper = new AsyncTargetWrapper();
asyncWrapper.Name = "AsyncRichTextBox";
asyncWrapper.WrappedTarget = target;

SimpleConfigurator.ConfigureForTargetLogging(asyncWrapper, LogLevel.Trace);