.net - IsDebugEnabled 与 Debug(Action<FormatMessageHandler>)

Question

In common logging V2.0当 LogLevel 高于日志条目时，有两种方法可以避免消息评估的成本:

if (Log.IsDebugEnabled)
    Log.Debug("Debug message");

或

Log.Debug(a => a("Debug message"));

哪种做法更好？有什么优缺点？

Answer 1

根据文档:

Leveraging lambdas, the ILog interface offers a new & safe way to write log statements

log.Debug( m=>m("value= {0}", obj.Value) );

This ensures, that the whole expression is only evaluated when LogLevel.Debug is enabled and thus saves you from having to write

if (log.IsDebugEnabled)
{
    log.Debug("value={0}", obj.Value);
}

to avoid this overhead.

因此您问题中的第二个选项被认为是最佳实践。