动态指定log4net日志文件名称

<param name="DatePattern" value="yyyyMMdd&quot;.log&quot;" />

    ‘‘‘ <summary>
    ‘‘‘ 动态指定日志文件名称
    ‘‘‘ </summary>
    ‘‘‘ <param name="logger">日志对象实例，log4net.ILog</param>
    ‘‘‘ <param name="fileName">日志输出的文件名</param>
    ‘‘‘ <remarks>一般在静态或初始化时调用</remarks>
    Public Shared Sub ChangeLogFileName(ByVal logger As ILog, ByVal fileName As String)
        Dim apdArray() As Appender.IAppender = logger.Logger.Repository.GetAppenders
        For Each apd As Appender.IAppender In apdArray
            If apd.GetType Is GetType(Appender.RollingFileAppender) Then
                logger.InfoFormat("Change Log File to {0}", fileName) ‘ 字符串会写入到 app.config 中指定的原始日志文件
                Dim rfa As Appender.RollingFileAppender = CType(apd, Appender.RollingFileAppender)
                rfa.File = fileName
                rfa.ActivateOptions()
                Exit For
            End If
        Next
    End Sub