A defined name is an alias for a cell or a range, so a formula can say SUM(SalesData). The Workbook holds them, and they round-trip through both reogrid-json and XLSX.

Defining a name

using unvell.ReoGrid.Core;
using unvell.ReoGrid.Core.Formula;

// workbook scope - the same name works from every sheet
wb.DefineName("TaxRate", "Sheet1!B1");
wb.DefineName("SalesData", "Sheet1!A2:C100", comment: "monthly sales");

// sheet scope - shadows a workbook-scoped name of the same spelling
wb.DefineName("Total", "Sheet2!D10", scope: "Sheet2");

ws.SetFormula(0, 0, "SUM(SalesData)");

The address is sheet-qualified (Sheet1!B1). A name can point at a single cell or a range.

Scope

When the same name exists at both workbook and sheet scope, the sheet-scoped one wins from that sheet (it shadows the other). This matches Excel.

Reading and removing

string? address = wb.GetName("TaxRate");             // "Sheet1!B1"
string? scoped = wb.GetName("Total", scope: "Sheet2");

foreach (DefinedNameInfo n in wb.GetNames())
	Console.WriteLine($"{n.Name} [{n.Scope ?? "workbook"}] = {n.Address}");

wb.RemoveName("TaxRate");

DefinedNameInfo is a record of Name / Scope / Address / Comment. A null Scope means workbook scope.

Resolving to a range

// resolve to a range (sheet scope wins)
RangePosition r = ws.ResolveRange("SalesData");

// ask the registry directly when you also need the target sheet
if (wb.Names.TryResolve("SalesData", fromSheet: ws.Name, out NameResolution res))
	Console.WriteLine($"{res.Sheet} {res.R1},{res.C1} - {res.R2},{res.C2}");

ws.ResolveRange(name) gives you a RangePosition, which carries no sheet information. When the name points at another sheet and you need to know which, use the NameResolution that wb.Names.TryResolve(...) returns.

Defining many at once

// define many at once with Bulk (it re-resolves once instead of every time)
wb.Names.Bulk(() =>
{
	for (int i = 0; i < 100; i++)
		wb.DefineName($"Row{i}", $"Sheet1!A{i + 1}");
});

Following structural changes

Persistence

• reogrid-json — round-trips as definedNames (compatible with the web edition)
• XLSX — round-trips as <definedNames>, at both workbook and sheet scope

Excel’s built-in names (_xlnm.*) do not appear in the list of defined names. The exceptions are the print area (_xlnm.Print_Area) and print titles (_xlnm.Print_Titles), converted into PrintSettings.PrintArea and PrintSettings.RepeatRows / RepeatColumns on load and back again on save (Printing and Page Setup). The other built-in names are not supported.

What to read next

• Formula References
• Addresses and Ranges