c# - 将自定义logentry类与自定义logformatter一起使用

我有一个自定义LogEntry类-ErrorEntry，它从LogEntry派生。它具有一些公共属性（类对象也是属性之一），我希望在其中添加其他数据。

public class ErrorEntry : LogEntry
{
 public string UserId {get; set; }
 public SessionDetail SessionInfo {get; set; }
}

我也有一个自定义格式化程序-MyFormatter

[ConfigurationElementType(typeof(CustomFormatterData))]
public class MyFormatter : ILogFormatter
{
  public MyFormatter(NameValueCollection nvc)
  {
     //not used
  }

  public string Format(LogEntry log)
  {
    string strEntry;
    if(log is ErrorEntry)
    {
       //use properties of ErrorEntry
       //populate returnString
    }
    else
    {
       throw new ArgumentException("Not supported");
    }
    return strEntry;
  }
}

我已经使用自定义格式化程序设置了web.config设置，并且在该语句检查变量是否为ErrorEntry类型的语句之前都可以正常工作-在这里，该变量永远不会变为true并进入else块。

我在这里有点困惑-我还需要做其他事情吗？定制格式化程序类是否支持此实现？

我正在使用企业库3.1。

最佳答案

如果我扩展LogFormatter（而不是实现ILogFormatter）并覆盖Format（），它将对我有用：

[ConfigurationElementType(typeof(CustomFormatterData))]
public class MyFormatter : LogFormatter
{
    public MyFormatter(NameValueCollection nvc)
    {
        //not used
    }

    public override string Format(LogEntry log)
    {
        ErrorEntry errorEntry = log as ErrorEntry;

        if (errorEntry != null)
        {
            return "This is the string with the custom values: " + errorEntry.UserId;
            //use properties of ErrorEntry
            //populate returnString
        }

        return "Not supported";
    }
}

连同此配置：

<?xml version="1.0"?>
<configuration>
  <configSections>
    <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=3.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <section name="dataConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings, Microsoft.Practices.EnterpriseLibrary.Data, Version=3.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
  </configSections>
  <loggingConfiguration name="Logging Application Block" tracingEnabled="true"
    defaultCategory="General" logWarningsWhenNoCategoriesMatch="true">
    <listeners>
      <add fileName="trace.log" header="----------------------------------------"
        footer="----------------------------------------" formatter="Custom Formatter"
        listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FlatFileTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=3.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
        traceOutputOptions="None" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FlatFileTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=3.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
        name="FlatFile TraceListener" />
    </listeners>
    <formatters>
      <add type="CustomFormatters.MyFormatter, CustomFormatters, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
        name="Custom Formatter" />
    </formatters>
    <categorySources>
      <add switchValue="All" name="General">
        <listeners>
          <add name="FlatFile TraceListener" />
        </listeners>
      </add>
    </categorySources>
    <specialSources>
      <allEvents switchValue="All" name="All Events" />
      <notProcessed switchValue="All" name="Unprocessed Category" />
      <errors switchValue="All" name="Logging Errors &amp; Warnings">
        <listeners>
          <add name="FlatFile TraceListener" />
        </listeners>
      </errors>
    </specialSources>
  </loggingConfiguration>
  <startup>
    <supportedRuntime version="v2.0.50727" />
  </startup>
</configuration>

如果不将ErrorEntry传递给Logger.Write（），则将构造LogEntry而不是自定义的ErrorEntry。因此，您应该始终传递ErrorEntry而不使用其他重载。例如。：

ErrorEntry errorEntry = new ErrorEntry();
errorEntry.UserId = "ME!";
errorEntry.Message = "Default message";
errorEntry.Categories.Add("General");

Logger.Write(errorEntry);