private string LegItemOnCache(ref LegendItem li)
{
Size sz = li.GetLegendSymbolSize();
Bitmap b = new Bitmap(sz.Width+1, sz.Height+1);
Graphics g = Graphics.FromImage(b);
li.LegendSymbol_Painted(g,new Rectangle(0,0,sz.Width,sz.Height));
string name = Guid.NewGuid().ToString();
MemoryStream MS = new MemoryStream();
b.Save(MS, System.Drawing.Imaging.ImageFormat.Png);
byte[] buffer = MS.ToArray();
HttpContext.Current.Cache.Insert(name, buffer, null, Cache.NoAbsoluteExpiration, TimeSpan.FromMinutes(15));
g.Dispose();
b.Dispose();
return name;
}
