I am new to Raspbian. I have a mono WinForms app on Raspbian on RPi + official 7" display. It works fine when I execute start-app.sh script via the UI (double click the file) and via the terminal (/home/pi/scannerapp/start-app.sh).
Script (start-app.sh):
#!/bin/bash
/usr/bin/mono '/home/pi/scannerapp/Re-Express Scanner WinForms.exe'
I edited the rc.local file with:
exec 2> /tmp/rc.local.log # send stderr from rc.local to a log file
exec 1>&2 # send stdout to the same log file
set -x # tell sh to display commands before execution
/home/pi/scannerapp/start-app.sh &
exit 0
And on boot, the app doesn't run. I find the following in the log:
Unhandled Exception:
System.TypeInitializationException: The type initializer for 'System.Windows.Forms.XplatUI' threw an exception. ---> System.ArgumentNullException: Could not open display (X-Server required. Check your DISPLAY environment variable)
Parameter name: Display
at System.Windows.Forms.XplatUIX11.SetDisplay (System.IntPtr display_handle) [0x00435] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUIX11..ctor () [0x00077] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUIX11.GetInstance () [0x0001c] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUI..cctor () [0x0007d] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
--- End of inner exception stack trace ---
at System.Windows.Forms.Application.EnableVisualStyles () [0x00006] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at Re_Express_Scanner_WinForms.Program.Main () [0x00001] in <52b5a9f59ae647c0a7c47e5736c3742e>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.TypeInitializationException: The type initializer for 'System.Windows.Forms.XplatUI' threw an exception. ---> System.ArgumentNullException: Could not open display (X-Server required. Check your DISPLAY environment variable)
Parameter name: Display
at System.Windows.Forms.XplatUIX11.SetDisplay (System.IntPtr display_handle) [0x00435] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUIX11..ctor () [0x00077] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUIX11.GetInstance () [0x0001c] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at System.Windows.Forms.XplatUI..cctor () [0x0007d] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
--- End of inner exception stack trace ---
at System.Windows.Forms.Application.EnableVisualStyles () [0x00006] in <d5b72d15d4f7424c8a1538e3f19ec2e3>:0
at Re_Express_Scanner_WinForms.Program.Main () [0x00001] in <52b5a9f59ae647c0a7c47e5736c3742e>:0
I get the same exception if I try to run the start-app.sh script via SSH.
Any help is appreciated. Thanks!
I ended up removing my edits from rc.local and made the call to the start-app.sh script in /etc/xdg/lxsession/LXDE-pi/autostart by editing it with sudo nano. That is now working on boot. From my understanding, calling the script from the rc.local file was doing so outside of the X display environment, hence the X display error and why it needed to be called from within the display environment (/lxde-pi/autostart) instead.
See this for more info on auto running GUI apps: http://www.raspberry-projects.com/pi/pi-operating-systems/raspbian/auto-running-programs-gui