C# of Visual Studio and R.Net not displaying any graph with ggplot2

Question

I have the following code to plot my input series using R charts from my C# application:

 FormatoPlot = string.Format("png('{0}',{1},{2})", plotTSPath.Replace('\\', '/'), pbPlotTS.Width, pbPlotTS.Height);
            objR.Evaluate(FormatoPlot);
            string ComandoPlot= "ploteo<-ggplot(ts_s, color= 'blue', linetype = 'solid', main='Serie Original de Tiempo')";
            objR.Evaluate("library(ggplot2)");
            objR.Evaluate("library(ggfortify)");
            objR.Evaluate(ComandoPlot);
            objR.Evaluate("print(ploteo)");
            objR.Evaluate("dev.off()");
            pbPlotTS.ImageLocation = plotTSPath;
            pbPlotTS.Refresh();
        }

My input is a time series, with normal plot works great, but when I use ggplot for a better design of graphic, ggplot doesn't work, only just shows a gray screen