Image Sources, Icons and the ImageList

Icons and Images in Wisej.NETModule 1The samples are ready before the course is: the module outline is on learnwisej.com, and the lessons, the knowledge checks and the hands-on labs follow when it launches — free, with an AI tutor in every lesson.

See the outline

One command panel whose four buttons carry their icons four different ways - a server-side System.Drawing.Image, a named theme image on ImageSource, and two controls sharing one ImageList through ImageKey - plus a diagnostics label that reads every control back through IImage and names the mechanism actually in play. This folder is the complete application at this point in the course, with its own solution and port.

The source of this sample

iceteagroup/LearnWisej-SamplesIcons and Images Course/Module 1

Browse this folder on GitHub

Or clone it: git clone https://github.com/iceteagroup/LearnWisej-Samples.git — then open IconDesk.slnx in Visual Studio and press F5.

Run it

cd "Icons and Images Course/Module 1/IconDesk"
dotnet run -f net10.0 --urls http://localhost:6201

Open http://localhost:6201. In Visual Studio, open IconDesk.slnx and press F5.

What to try

Action	Expected result
Look at the diagnostics label	Each control is named with the mechanism behind its icon. btnOpen reports an Image, btnSave an ImageSource, the rest an ImageList entry.
Press Replace the image under the key	The bin becomes a grey cross on both btnDelete and lblDeleteEcho. Neither control was assigned to - only the entry under the key "delete" changed.
Press it again	Both go back. The key is the contract; the picture behind it is free to change.
Press Set Image and ImageSource on one button	The status line reports Image still set afterwards: False. Assigning ImageSource cleared Image; they feed one slot.
Press Inspect through IImage	The report is rebuilt from the live controls, so it always describes the current state rather than the startup state.
Open the browser network panel and reload	btnOpen and the ImageList pictures arrive as component.wx requests (server-rendered PNG). The theme icon does not - it comes inline with the theme.

Notes for anyone extending the panel

• Image and ImageSource are mutually exclusive. Assigning ImageSource sets Image to null, verified in btnSetBoth_Click. Nothing warns you, so a lost icon is usually a second assignment somewhere else rather than a missing file.
• A control fed from an ImageList still returns a picture from Image. Test ImageList and ImageKey before Image or every keyed control looks like an image-object control.
• ImageList.Images["key"] is read-only as an assignment target. It returns the live ImageListEntry; set entry.Image to repoint the key.
• Image.FromFile keeps the file locked for the lifetime of the image, which is the last thing a server application wants. LoadServerImage reads the bytes and builds the image from a MemoryStream instead.
• Application.MapPath("Images/open.png") resolves whether the application runs from bin/ or from a published folder. The Images folder is copied to the output by the .csproj, because the browser also fetches some of these files by relative URL in later modules.