How to export the charts to PDF in Xamarin.Android

        void ExportToPdfButton_Click(object sender, EventArgs e)
        {
            ExportChart ("SfChart", sfChart);
        }
 
        public void ExportChart(string filename, object obj)
        {
            var nativechart = obj as Com.Syncfusion.Charts.SfChart;
            nativechart.DrawingCacheEnabled = true;
            nativechart.SaveEnabled = true;
            using (Bitmap bitmap = nativechart.DrawingCache)
            {
                Java.IO.File imagePath = new Java.IO.File(Android.OS.Environment.ExternalStorageDirectory + "/Pictures/" + filename);
                imagePath.CreateNewFile();
                using (Stream fileStream = new FileStream(imagePath.AbsolutePath, FileMode.OpenOrCreate))
                {
                    try
                    {
                        bitmap.Compress(Android.Graphics.Bitmap.CompressFormat.Jpeg, 100, fileStream);
 
                        //Create a new PDF document.
 
                        Syncfusion.Pdf.PdfDocument document = new Syncfusion.Pdf.PdfDocument();
                        PdfPage page = document.Pages.Add();
                        PdfGraphics graphics = page.Graphics;
                        graphics.DrawImage(PdfImage.FromStream(fileStream), 0, 20, page.GetClientSize().Width, page.GetClientSize().Height-15);
                        MemoryStream stream = new MemoryStream();
                        document.Save(stream);
                        document.Close(true);
                        SavePDF("Chart.pdf", "application/pdf", stream);
                    }
                    finally
                    {
                        fileStream.Flush();
                        fileStream.Close();
                        nativechart.DrawingCacheEnabled = false;
                    }
                }
            }
        }
 
        void SavePDF(string fileName, String contentType, MemoryStream stream)
        {
            string root = null;
            if (Android.OS.Environment.IsExternalStorageEmulated)
            {
                root = Android.OS.Environment.ExternalStorageDirectory.ToString();
            }
            else
                root = System.Environment.GetFolderPath(System.Environment.SpecialFolder.MyDocuments);
 
            Java.IO.File myDir = new Java.IO.File(root + "/Syncfusion");
            myDir.Mkdir();
 
            Java.IO.File file = new Java.IO.File(myDir, fileName);
 
            if (file.Exists()) file.Delete();
 
            try
            {
                FileOutputStream outs = new FileOutputStream(file);
                outs.Write(stream.ToArray());
 
                outs.Flush();
                outs.Close();
            }
            catch (Exception e)
            {
 
            }
            if (file.Exists())
            {
                Android.Net.Uri path = Android.Net.Uri.FromFile(file);
                string extension = Android.Webkit.MimeTypeMap.GetFileExtensionFromUrl(Android.Net.Uri.FromFile(file).ToString());
                string mimeType = Android.Webkit.MimeTypeMap.Singleton.GetMimeTypeFromExtension(extension);
                Intent intent = new Intent(Intent.ActionView);
                intent.SetDataAndType(path, mimeType);
                this.StartActivity(Intent.CreateChooser(intent, "Choose App"));
            }
        }