ReoGrid V4
新機能のご紹介

// ワークシートの行数を設定（例：100万行）
worksheet.SetRows(1000000);

// データソースを遅延読み込みモードで設定
worksheet.AddDataSource(
    new RangePosition(0, 0, 1000000, 10),
    new MyDataSource(logs),
    DataSourceLoadMode.LazyLoading
);

var extensionHeader = worksheet.ExtensionColumnHeader;
extensionHeader.SetRowCount(3);
extensionHeader.MergeCells(0, 1, 2, 1);
extensionHeader[0, 1].Text = "大分類";

var ds = new MyDataSource();

// A1:G30 は格納先の範囲アドレス
sheet.AddDataSource("A1:G30", ds);

var myRange = sheet1.Ranges["G1:G3000"];
var dropdownList1 = new DropdownListCell(myRange);
sheet1.Cells["A1"].Body = dropdownList1;

cell1.DataFormat = CellDataFormatFlag.Number;
cell1.DataFormatArgs = "#,##0;[Red]-#,##0";

sheet.OutlineButtonLocation = OutlineButtonLocation.Top;

var outlineGroup = sheet.GetOutlineGroup(RowOrColumn.Row, 0);
outlineGroup.CollapseAll();
outlineGroup.ExpandAll();

var filter = new ConditionalDataFilter();
var condition = new FilterCondition(
    2, ConditionOperator.NotEquals, "USD");
filter.Conditions.Add(condition);
sheet.DoFilter("A1:G30", filter);

var rule1 = new Rule("THIS > 1000", "A1:Z30",
    new WorksheetRangeStyle {
        Flag = PlainStyleFlag.TextColor,
        TextColor = SolidColor.Yellow,
    });
sheet.ConditionalStyles.Add(rule1);

var session = new HighlightTextSearchSession(
    Workbook, txtKeyword.Text,
    Workbook.CurrentWorksheet);
session.Search();
session.MarkAllResultHighlight(SolidColor.Goldenrod);
session.NextMatch();

// すべてのセルをロック
sheet.IsLocked = true;

// C5 セルのみ解除
sheet.Cells["C5"].IsLocked = CellLock.UnLocked;

worksheet.SetRows(0);

sheet.Options.FormulaCalculationPrecision =
    FormulaCalculationPrecision.LowPrecision;

ReoGridControl.EnableUIAutomation = true;

var reoGrid = session
    .FindElementByClassName("ReoGridControl");
reoGrid.Click();