NLog回调可能吗? [英] NLog callback possible?

问题描述

我正在将自行开发的日志记录系统转换为NLog，并且想知道是否有办法将事件添加到Logger或以其他方式支持一种机制，当我记录消息时，可以使用最终格式化的消息和LogLevel.我目前使用类似的方法将服务器消息发送回连接的客户端.

I am in the process of converting a home grown logging system to NLog and am wondering if there is a way to add an event to a Logger or otherwise support a mechanism where when I log a message I can get a callback with the final formatted message and the LogLevel. I currently use something like this to send server messages back to a connected client.

Thx

推荐答案

这是我在评论中所讨论的内容的MCVE.创建一个接受一些回调函数的目标:

This is an MCVE of what I was talking about in the comments. Create a target that accepts some callback functions:

[Target("MyFirst")]
public sealed class MyFirstTarget : TargetWithLayout
{
    private readonly Action<string>[] _callbacks;

    public MyFirstTarget(params Action<string>[] callbacks)
    {
        _callbacks = callbacks;
    }

    protected override void Write(LogEventInfo logEvent)
    {
        foreach (var callback in _callbacks)
        {
            callback(logEvent.FormattedMessage);
        }
    }
}

配置NLog以使用目标.由于回调是在构造函数中传递的，因此我以编程方式进行了此操作.您还可以在NLog.config中配置目标，但是您的目标必须是单例，然后才能在代码中注册回调.

Configure NLog to use the target. I do this programmatically since the callbacks are passed in the constructor. You can also configure the target in the NLog.config, but your target will need to be a singleton then so you can register the callbacks in code.

class Program
{
    public static void Main()
    {
        LogManager.Configuration.AddTarget("MyFirst", new MyFirstTarget(s => Debug.WriteLine(s)));

        var logger = LogManager.GetCurrentClassLogger();
        logger.Debug("test");
    }
}

在没有其他NLog配置的情况下(将此代码复制到一个空项目中并添加NLog nuget包)，这将向您的调试窗口发送一条消息.

With no other NLog configuration (copy this code into an empty project and add the NLog nuget package), this will emit a message to your debug window.

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