Custom MSBuild logger - grabs only High importance messages, returns them as a string.

HighImportanceStringLogger.cs

    class HighImportanceStringLogger : ILogger
    {
        readonly private StringBuilder stringBuilder = new StringBuilder();

        public void Initialize(IEventSource eventSource)
        {
            eventSource.MessageRaised += eventSource_MessageRaised;
        }

        void eventSource_MessageRaised(object sender, BuildMessageEventArgs e)
        {
            if (e.Importance <= MessageImportance.High)
            {
                stringBuilder.AppendLine(e.Message);
            }
        }

        public string Parameters { get; set; }

        public void Shutdown() { }

        public LoggerVerbosity Verbosity { get; set; }

        public override string ToString()
        {
            return this.stringBuilder.ToString();
        }
    }