事件监听器EventListener使用研究，能够拦截框架内部动作，例如http请求等，不同版本框架的事件没有统一

NewLife.Core/Log/LogEventListener.cs

@@ -0,0 +1,95 @@
+#if !NET4
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Tracing;
+
+namespace NewLife.Log
+{
+    /// <summary>日志事件监听器。用于监听内置事件并写入日志</summary>
+    public class LogEventListener : EventListener
+    {
+        private readonly HashSet<String> _hash = new HashSet<String>();
+        private readonly HashSet<String> _hash2 = new HashSet<String>();
+
+        /// <summary>实例化</summary>
+        /// <param name="sources"></param>
+        public LogEventListener(String[] sources)
+        {
+            foreach (var item in sources)
+            {
+                _hash.Add(item);
+            }
+        }
+
+        /// <summary>创建事件源。此时决定要不要跟踪</summary>
+        /// <param name="eventSource"></param>
+        protected override void OnEventSourceCreated(EventSource eventSource)
+        {
+            if (_hash.Contains(eventSource.Name))
+            {
+                var log = XTrace.Log;
+
+                var level = log.Level switch
+                {
+                    LogLevel.All => EventLevel.LogAlways,
+                    LogLevel.Debug => EventLevel.Verbose,
+                    LogLevel.Info => EventLevel.Informational,
+                    LogLevel.Warn => EventLevel.Warning,
+                    LogLevel.Error => EventLevel.Error,
+                    LogLevel.Fatal => EventLevel.Critical,
+                    LogLevel.Off => throw new NotImplementedException(),
+                    _ => EventLevel.Informational,
+                };
+
+                EnableEvents(eventSource, level);
+            }
+            else if (!_hash2.Contains(eventSource.Name))
+            {
+                _hash2.Add(eventSource.Name);
+
+                XTrace.WriteLine($"Source={eventSource.Name}");
+            }
+        }
+
+        /// <summary>写入事件。监听器拦截，并写入日志</summary>
+        /// <param name="eventData"></param>
+        protected override void OnEventWritten(EventWrittenEventArgs eventData)
+        {
+            var log = XTrace.Log;
+
+            var level = eventData.Level switch
+            {
+                EventLevel.Informational => LogLevel.Info,
+                EventLevel.LogAlways => LogLevel.All,
+                EventLevel.Critical => LogLevel.Fatal,
+                EventLevel.Error => LogLevel.Error,
+                EventLevel.Warning => LogLevel.Warn,
+                EventLevel.Verbose => LogLevel.Debug,
+                _ => LogLevel.Info,
+            };
+
+#if NET45
+            XTrace.WriteLine($"#{eventData.EventSource?.Name} ID = {eventData.EventId}");
+            for (var i = 0; i < eventData.Payload.Count; i++)
+            {
+                XTrace.WriteLine($"\tPayload = \"{eventData.Payload[i]}\"");
+            }
+#elif NET50
+            XTrace.WriteLine($"#{eventData.EventSource?.Name} ThreadID = {eventData.OSThreadId} ID = {eventData.EventId} Name = {eventData.EventName}");
+            for (var i = 0; i < eventData.Payload.Count; i++)
+            {
+                XTrace.WriteLine($"\tName = \"{eventData.PayloadNames[i]}\" Value = \"{eventData.Payload[i]}\"");
+            }
+#else
+            XTrace.WriteLine($"#{eventData.EventSource?.Name} ID = {eventData.EventId} Name = {eventData.EventName}");
+            for (var i = 0; i < eventData.Payload.Count; i++)
+            {
+                XTrace.WriteLine($"\tName = \"{eventData.PayloadNames[i]}\" Value = \"{eventData.Payload[i]}\"");
+            }
+#endif
+
+            if (!eventData.Message.IsNullOrEmpty()) log.Write(level, eventData.Message);
+        }
+    }
+}
+#endif

Test/Program.cs

@@ -44,6 +44,21 @@ private static void Main(String[] args)
             set.Debug = true;
             set.LogLevel = LogLevel.All;
 
+            new LogEventListener(new[] {
+                "System.Runtime",
+                "System.Diagnostics.Eventing.FrameworkEventSource",
+                "System.Transactions.TransactionsEventSource",
+                "Microsoft-Windows-DotNETRuntime",
+                //"Private.InternalDiagnostics.System.Net.Sockets",
+                "System.Net.NameResolution",
+                //"Private.InternalDiagnostics.System.Net.NameResolution",
+                "System.Net.Sockets",
+                //"Private.InternalDiagnostics.System.Net.Http",
+                "System.Net.Http",
+                //"System.Data.DataCommonEventSource",
+                //"Microsoft-Diagnostics-DiagnosticSource",
+            });
+
             var set2 = XCode.Setting.Current;
             set2.Debug = true;
 #endif
@@ -54,7 +69,7 @@ private static void Main(String[] args)
                 try
                 {
 #endif
-                Test7();
+                Test5();
 #if !DEBUG
                 }
                 catch (Exception ex)
@@ -154,7 +169,7 @@ private static void Test2()
 
         private static void Test3()
         {
-            var tracer = DefaultTracer.Instance;
+            var tracer = DefaultTracer.Instance ?? new DefaultTracer();
             tracer.MaxSamples = 100;
             tracer.MaxErrors = 100;
 

Test/Test.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net45;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>net45;netcoreapp3.1;net5.0</TargetFrameworks>
     <OutputPath>..\..\Test\</OutputPath>
     <LangVersion>latest</LangVersion>
     <Version>1.0.0.1130</Version>
@@ -27,9 +27,9 @@
   <PropertyGroup Condition="'$(TargetFramework)'=='net40'">
     <DefineConstants>$(DefineConstants);__WIN__;NET4</DefineConstants>
   </PropertyGroup>
-  <ItemGroup>
-    <PackageReference Include="System.Data.SQLite" Version="1.0.113.6" />
-  </ItemGroup>
+  <PropertyGroup Condition="'$(TargetFramework)'=='net5.0'">
+    <DefineConstants>$(DefineConstants);__CORE__;NET50</DefineConstants>
+  </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\NewLife.Core\NewLife.Core.csproj" />
     <ProjectReference Include="..\XCode\XCode.csproj" />