No rendering image if RDP is disconnected

Question

I have a question for SfChart (WPF) exporting:

when I use RDP (Remote Desktop) and try to export SfChart, the program works well. I can get the correct image as expected.

But after I disconnect RDP and let the program keeps exporting images.

The exported image files will be empty(blank)... How could I fix this issue?

Devakumar Dhanapoosanam · Answer

Hi Weichung,Query: But after I disconnect RDP and let the
program keeps exporting images. The exported image files will be
empty(blank)... How could I fix this issue?We have checked the reported query and exported the chart
image by using the chart Save method, exported image renders proper at our end while
chart is added in the visual tree and even when the remote desktop machine is disconnected
while export. Please find the tested sample from the attachment below.Also, we would like to let you know that chart will
export as image properly when chart is added on the visual tree otherwise it
will export as black image. You can export the chart to image without rendering
in UI by setting the chart to RootVisual in HwndSource and
passing HwndSourceParameters to the HwndSource. Please refer below link for more details. https://help.syncfusion.com/wpf/charts/exporting#export-sfchart-to-image-without-rendering-in-ui
Since we are not clear about the exact requirement how
the remote desktop run and whether the
chart is added in the visual tree during export when disconnected.Could you please revert us by modifying the sample with
issue reproduced state or share pictorial/video representation of issue with
replication steps which will be helpful to provide you better solution at the
earliest.Regards,Devakumar DAttachment: SF_177857_4ff9daeb.zip

Weichung · Answer

Hi  Devakumar Dhanapoosanam,Thanks a lot.I tried the sample project you provided, but the test result was same. The exported images are blank.The attachment is the screen recording video file.The OS of remote machine is Windows 11 (build 22000.978).BTW, I'd tried "Without UI rendering method" before, the result was same (i.e., blank image).Maybe the issue comes from the bug of Microsoft WPF render engine.I found such kind discussion:

System.Windows.Media.Imaging.RenderTargetBitmap.Render does not render from remote desktop · Issue #3765 · dotnet/wpf · GitHub

Some people had reported similar issues and mentioned "Hi,In Windows server datacenter 2019 version 17763.2114 there is no problem.In Windows server datacenter 2022 version 20348.405 we got this problem.When we connected to the user on the remote desktop everything is ok and WPF will render the views.but when we disconnect from remote desktop, WPF cannot render the bitmap."Regards,PatrickAttachment: 20220930_234127_4e1a2705.zip

Devakumar Dhanapoosanam · Answer

Hi Weichung,Thanks for the update.We will validate and update the complete details in two
business days on or before October 5, 2022.Regards,Devakumar D

Devakumar Dhanapoosanam · Answer

Hi Weichung,We were able to reproduce the reported problem when RDP is disconnected, the exported chart image is blank. As you have already found that “Maybe the issue comes
from the bug of Microsoft WPF render engine” the reported problem occurs even
when export using RenderTargetBitmap getting blank while RDP is disconnected.

So, this is a framework level issue in RenderTargetBitmap
and you can follow up the below reported GitHub issue link for further updates.https://github.com/dotnet/wpf/issues/3765
Please let us know if you need any further assistance.Regards,Devakumar D

Weichung · Answer

Hi

Devakumar,Thanks a lot.Regards,Patrick Chang

Devakumar Dhanapoosanam · Answer

Hi Weichung,Thanks for your update.Please let us know if you need any further assistance.Regards,Devakumar D