Leading rows and columns can be pinned so that scrolling does not move them.

Setting it

control.SetFreeze(rows: 1, cols: 0);   // freeze row 1
control.SetFreeze(1, 1);               // freeze row 1 and column A
control.SetFreeze(0, 0);               // unfreeze

The same API on all three controls (WinForms, WPF and Avalonia).

Working with the viewport directly, it is viewport.FrozenRows / viewport.FrozenCols.

using unvell.ReoGrid.Core;
using unvell.ReoGrid.Core.Rendering;

viewport.FrozenRows = 1;      // freeze row 1
viewport.FrozenCols = 1;      // freeze column A

// size of the frozen area in logical pixels; only the rest scrolls
double h = viewport.FrozenHeight;
double w = viewport.FrozenWidth;

double scrollableH = viewport.ScrollableContentHeight;
double scrollableW = viewport.ScrollableContentWidth;

It is view state

V4 kept this on the model, as worksheet.FreezeToCell(r, c) plus a FreezeArea enum. In V5 it is view state.

That has consequences.

• Showing one worksheet through several views gives each its own freeze
• It is irrelevant headless (nothing is drawn)
• It is not saved yet — reopening a file comes back unfrozen

Persisting a per-sheet freeze position is future work.

Relationship to scrolling

The frozen area is always drawn; only the scrollable part moves.

Relationship to printing

Freezing is for the screen and has no effect on printing. To repeat the leading rows on every page, use print titles (PrintSettings.RepeatRows / RepeatColumns) instead (Printing and Page Setup).

What to read next

• The Viewport
• Zoom