The ImageTransferMethod property lists how the chart data is transferred to the source attribute of the <IMG> tag. ImageTransferEnum.Session places the chart data (byte array) into a Session variable, while ImageTransferEnum.Cache places the chart data into a Cache variable. ImageTransferEnum.File writes chart data to a temporary file.
This property only applies to the Manual, HTTPHandler, and ASP Page rendering methods. The following table lists what the effect of an intersection between a transfer method and render method produces:
| Transfer Method | |||
Render Method | None | Session | Cache | File |
Manual | - no tag. - no image transfer. | - no tag. - image transfer in session variables. | - no tag. - image transfer by application cache. | - no tag. - image written to file. |
HttpHandler | - tag contains reference to the handler specified by the ImageUri property, including parameters. - no image transfer. | - tag contains session references. - image transfer in session variables. - auto delete variables. - session variables deleted with session termination. | - tag contains cache references. - image transfer in cache variables. - auto delete variables. - cache variables expire for cleanup. | - tag contains the reference. - image transfer by filename. - auto delete file. |
ASP Page | - tag contains reference to ASP page specified by the ImageUri property, including parameters. - no image transfer. | - tag contains session references. - image transfer in session variables. - session variables deleted with session termination. | - tag contains cache references. - image transfer in cache variables. - cache variables expire for cleanup. | - n/a – exception thrown. |
File | - tag contains reference to file specified by ImageUri. External file cleanup required. | - n/a – not used. | - n/a – not used. | - n/a – not used. |
BinaryWrite | - no tag. - renders binary stream containing chart image to page response. | - n/a – not used. | - n/a – not used. | - n/a – not used. |