source: Include/Classes/System/Diagnostics/TraceListener.ab@ 69

' リスナ
Class TraceListener
    indentLevel As Long
    indentSize As Long

Protected
    Function GetIndentString() As String
        Dim i As Long

        Dim IndentStr = ""
        For i = 0 To ELM( indentSize )
            IndentStr = IndentStr + " "
        Next

        Dim ResultStr = ""
        For i = 0 To ELM( indentLevel )
            ResultStr = ResultStr + IndentStr
        Next

        Return ResultStr
    End Function

Public
    Sub TraceListener()
        indentLevel = 0
        indentSize = 4
    End Sub

    ' コピーコンストラクタ
    Sub TraceListener( ByRef listener As TraceListener )
        memcpy( VarPtr( This ), VarPtr( listener ), SizeOf( TraceListener ) )
    End Sub


    '----------------------------------------------------------------
    ' パブリック コンストラクタ
    '----------------------------------------------------------------

    Virtual Sub Write( message As String )
        '派生クラスで実装 (基底では何もしない）
    End Sub
    Virtual Sub Write( value As Object )
        Write( value.ToString() )
    End Sub
    Virtual Sub Write( value As Object, category As String )
        Write( category + ": " + value.ToString() )
    End Sub
    Virtual Sub Write( message As String, category As String )
        Write( category + ": " + message )
    End Sub

    Virtual Sub WriteLine( message As String )
        '派生クラスで実装 (基底では何もしない）
    End Sub
    Virtual Sub WriteLine( value As Object )
        WriteLine( value.ToString() )
    End Sub
    Virtual Sub WriteLine( value As Object, category As String )
        WriteLine( category + ": " + value.ToString() )
    End Sub
    Virtual Sub WriteLine( message As String, category As String )
        WriteLine( category + ": " + message )
    End Sub


    '----------------------------------------------------------------
    ' パブリック プロパティ
    '----------------------------------------------------------------

    ' IndentLevelプロパティ
    Function IndentLevel() As Long
        Return indentLevel
    End Function
    Sub IndentLevel( indentLevel As Long )
        This.indentLevel = indentLevel
    End Sub

    ' IndentSizeプロパティ
    Function IndentSize() As Long
        Return indentSize
    End Function
    Sub IndentSize( size As Long )
        indentSize = size
    End Sub
End Class

' デフォルトリスナ（デバッガビューへの出力）
Class DefaultTraceListener
    Inherits TraceListener
Public

    Override Sub Write( message As String )
        ' デバッグビューへ出力
        Dim tempStr = GetIndentString() + message
        OutputDebugString( tempStr )

        ' デバッグログへ書き込む
        ' TODO: 実装
    End Sub

    Override Sub WriteLine( message As String )
        Write( GetIndentString() + message + Ex"\r\n" )
    End Sub
End Class