Ubuntu server 20.04 / C# Discord Bot (Net.5.0) "Parameter is not valid."-CodePudding

I decided to let my bot run on my new home server. So I moved it there via git and the bot does run etc. However, I get the following error when I am using a command where images are being processed with System.Drawing:

System.ArgumentException: Parameter is not valid.
   at System.Drawing.SafeNativeMethods.Gdip.CheckStatus(Int32 status)
   at System.Drawing.Bitmap..ctor(String filename, Boolean useIcm)
   at Aurelia.ImageProcessor.ImageBuilder(String filename, String idolname, String group, String rarity, Int32 rar, String id, String pathDefiner) in /home/aurelia/discordBots/Aurelia/AureliaBot/Aurelia/ImageProcessor.cs:line 21

(Aurelia is my bot's name)

If I debug it in VS on my home pc, I don't get this error, and it works fine. The first few times, the bot actually send a picture, but it was a wrong picture. So now, I have no clue what to do. I checked every parameter, every parameter should be fine.

The code for the bitmap:

                Bitmap cardTemp = new Bitmap($"assets\\groups\\{group}\\{idolname}\\{filename}");
                Bitmap card = new Bitmap(cardTemp, 800, 1200);
                Bitmap rareFrameTemp = new Bitmap($"assets\\frames\\{rarity}Frame.png");

Only the first line throws the error, and yes the file exists. Thank you!

CodePudding user response：

The issue is that your paths, while they work for Windows, will not work for Unix based systems as they use forward slashes - / - not backward slashes \ as a directory separator character.

Use Path.Combine for a cross-platform solution.

It will use the Path.DirectorySeparatorChar which will provide a platform-specific character:

var cardTempPath = Path.Combine("assets", "groups", group, idolname, filename);
var rareFrameTemp = Path.Combine("assets", "frames", $"{rarity}Frame.png");

Bitmap cardTemp = new Bitmap(cardTempPath);
Bitmap card = new Bitmap(cardTemp, 800, 1200);
Bitmap rareFrameTemp = new Bitmap(rareFrameTemp);