Merged Cells — ReoGrid Docs

Merges are held by ws.Merges (a MergeTable), separately from cell values. Cells that are not merged never appear in it, so the cost is proportional to the number of merges — not to the size of the sheet.

A merged B2:D3; no grid lines are drawn inside it

Merging and unmerging

using unvell.ReoGrid.Core;

ws.MergeRange(RangePosition.Parse("B2:D3"));

bool merged = ws.Merges.IsMerged(1, 1);
bool isAnchor = ws.Merges.IsAnchor(1, 1);      // is this the top-left cell?

ws.UnmergeAt(1, 1);                            // any cell inside the range will do

Once merged, the value and formatting of the range’s top-left cell (the anchor) is what gets displayed. UnmergeAt removes the whole merge no matter which cell inside it you name.

Inspecting

if (ws.Merges.TryGetAt(1, 1, out var range))
	Console.WriteLine(range.ToAddress());      // "B2:D3"

int count = ws.Merges.Count;
foreach (var r in ws.Merges.Ranges)
	Console.WriteLine(r.ToAddress());

TryGetAt returns the full merged range from any cell inside it.

Growing a selection to whole merges

// when the selection clips a merged cell, grow it to cover the whole merge
RangePosition full = ws.Merges.ExpandToIncludeMerges(selection);

Use this when deciding what a copy or a formatting change should apply to. Acting on part of a merge makes the display and the underlying data disagree, so — as in Excel — growing the range is the default behaviour.

Insert and delete

Merged ranges follow row and column insertion and deletion automatically. When a deletion removes a merged range entirely, the merge itself goes away with it.

Limits

A range containing merges cannot be sorted. Sorting rejects such a range. Excel has the same restriction

Members of `MergeTable`

Member	What it does
`IsMerged(r, c)`	Is this cell part of a merge?
`IsAnchor(r, c)`	Is this the merge’s top-left cell?
`TryGetAt(r, c, out range)`	The merged range containing this cell
`Ranges` / `Count`	The merges, and how many there are
`ExpandToIncludeMerges(range)`	Grows a range out to whole merges
`Clear()`	Removes every merge

Add and remove through ws.MergeRange(...) / ws.UnmergeAt(...) — driving the table directly skips the related bookkeeping.