How to export an mschart chart to excel?

I have created a chart with Mschart.I want to export the created chart to excel.
I'm using following code but when I open it in excel I just see some unknown code instead of chart.

using (var chartimage = new MemoryStream())
 {
     ChartAmalkerd.SaveImage(chartimage, ChartImageFormat.Png);
     ExportToExcel(chartimage.GetBuffer());
 }
 private void ExportToExcel(byte[] input)
 {
     string attachment = "attachment; filename=Employee.xls";
     Response.ClearContent();
     Response.ContentEncoding = Encoding.GetEncoding(1256);
     Response.AddHeader("content-disposition", attachment);
     Response.ContentType = "application/vnd.ms-excel";
     Response.Buffer = true;
     this.EnableViewState = false;
     Response.BinaryWrite(input);
     Response.Flush();
     Response.Close();
     Response.End();
 
 }
 

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