What you are building
Gridlane is a spreadsheet you assemble in twelve short stages. The teaching stack is WPF (C#, WPF, CSV workbook storage). By the end you should understand the shell, the data you persist, and the everyday workflows people expect from this kind of app.
WPF’s DataGrid is a natural teaching surface for cells, formulas-lite, and clipboard paste—without building a full Excel clone.
Bind a 2D cell model to the grid. Keep parsing and file I/O out of code-behind event handlers as the sheet grows.
Work in order. Early folders are intentionally small so you can see the window (or server) boot before features pile on. From the data-layer part onward, each snapshot should still run after you install dependencies.
Read the goal, clone the matching GitHub folder, run it, then skim the code against the notes below. If something fails, fix the run path first—most “bugs” on day one are the wrong directory or a skipped install.
Parts in order
Each chapter below is one checkpoint. Open a part when you are ready for that feature—not all at once.