A Worksheet is one sheet. Reading and writing cells, formulas, styles, and inserting or deleting rows and columns all happen here. It raises no events — when you need change notifications, use the control’s events (Events).

Reading and writing values

using unvell.ReoGrid.Core;
using unvell.ReoGrid.Core.Style;

ws.SetNumber(0, 0, 1200);
ws.SetText(0, 1, "Notebook");
ws.SetBoolean(0, 2, true);

// when the type is only known at run time
ws.SetObjectValue(0, 3, DateTime.Today);

object? raw = ws.GetObjectValue(0, 0);       // double / string / bool / DateTime / null
string shown = ws.GetDisplayText(0, 0);      // the display string with the number format applied

ws.ClearCell(0, 3);

The typed SetNumber / SetText / SetBoolean are what you normally use. SetObjectValue is the entry point for when the type is only known at run time; it sorts the value into the right kind for you.

There are three ways to read, depending on what you want back.

GetFormattedText(r, c, out uint? color) returns the display string plus the text color the format code asks for ([Red] and friends).

Formulas

ws.SetFormula(2, 0, "SUM(A1:A2)");      // no leading '='
bool has = ws.HasFormula(2, 0);
string? text = ws.GetFormula(2, 0);

ws.ClearFormula(2, 0);
ws.Recalculate();                        // recalculate everything, e.g. after a bulk load

SetFormula parses the formula, records its dependencies, and recalculates that cell and everything that depends on it. You do not normally need Recalculate(); it is for when you want to redo everything at once, such as right after loading an xlsx.

Styles

ws.SetCellStyle(0, 0, new StyleRecord { Bold = true });
ws.SetRowStyle(0, new StyleRecord { BackgroundColor = 0xFFEFEFEF });
ws.SetColumnStyle(3, new StyleRecord { TextAlign = HAlign.Right });

ws.RootStyle = ws.RootStyle with { FontFamily = "Segoe UI", FontSize = 11f };

// the result of resolving Cell < Row < Column < Sheet
StyleRecord effective = ws.GetEffectiveStyle(0, 0);

RootStyle is the default for the whole sheet. See Style Inheritance for how the levels combine.

Inserting and deleting rows and columns

ws.InsertRows(3, 2);       // insert two rows at row 3
ws.DeleteRows(10, 1);
ws.InsertColumns(1, 1);
ws.DeleteColumns(5, 3);

Cell values are not the only thing that moves: merges, borders, cell types, conditional formats, row and column metadata, and formula references all follow along. A reference that pointed into a deleted range becomes #REF!.

The used range

if (ws.TryGetUsedRange(out var used))
{
	// false on an empty sheet. Clamp any full-range loop with this
	Console.WriteLine($"{used.ToAddress()} / {used.CellCount} cells");
}

Always clamp here before writing anything that iterates the sheet. A default sheet has 1,048,576 rows, so a naive loop effectively never finishes.

Visiting only the cells that exist

// visits only cells that exist; empty ones never call back
ws.ReadWindow(0, 0, rows: 50, cols: 20, (row, col, value, styleId) =>
{
	Console.WriteLine($"{row},{col} = {value.Kind}");
});

ReadWindow visits only cells that hold a value inside the window you give it. It beats a double loop clamped to the used range, and it is what rendering and export use.

The cell cursor

ws.Cell(0, 0).SetNumber(10);
ws.Cell("B2").SetText("hello").SetStyle(new StyleRecord { Italic = true });

var cursor = ws.Cell("C3");
if (!cursor.IsEmpty)
	Console.WriteLine(cursor.ObjectValue);

The CellCursor that Cell(...) returns is a struct that remembers a position, so it allocates nothing. It reads better when you do several things to the same cell.

Default sizes

ws.SetDefaultSizes(rowHeight: 24, columnWidth: 100);

double dr = Worksheet.DefaultRowHeight;      // 20 (logical pixels)
double dc = Worksheet.DefaultColumnWidth;    // 80

For individual row heights and column widths, see Rows and Columns.

Everything that is not a cell value

Information that a single cell value cannot express — a merge, a border — lives on its own property.

The Has* properties — HasImages, HasCellTypes, HasConditionalFormats, HasRowOutlines — are safe to call on a sheet that has never used the feature. They answer without building anything, so calling them every frame is fine.

Performance notes

• Think in used ranges, not sheet dimensions. Clamp with TryGetUsedRange, or use ReadWindow
• Whole-row and whole-column formatting belongs on SetRowStyle / SetColumnStyle. Walking the cells makes the work proportional to the sheet’s dimensions
• The model raises no events. To detect changes, listen on the control

What to read next

• CellValue
• Addresses and Ranges
• Performance and Memory