如何使用closedxml将单元格与动态列计数合并？

using ClosedXML.Excel;

// 创建一个新的Excel工作簿
var workbook = new XLWorkbook();

// 添加一个工作表
var worksheet = workbook.Worksheets.Add("Sheet1");

// 添加表头
worksheet.Cell(1, 1).Value = "列1";
worksheet.Cell(1, 2).Value = "列2";
worksheet.Cell(1, 3).Value = "列3";

// 添加数据
for (int i = 2; i <= 10; i++)
{
    worksheet.Cell(i, 1).Value = "数据" + (i - 1);
    worksheet.Cell(i, 2).Value = "数据" + (i - 1);
    worksheet.Cell(i, 3).Value = "数据" + (i - 1);
}

// 保存Excel文件
workbook.SaveAs("Sample.xlsx");

using ClosedXML.Excel;

// 打开Excel文件
var workbook = new XLWorkbook("Sample.xlsx");

// 获取工作表
var worksheet = workbook.Worksheet("Sheet1");

// 获取数据的起始行和列
int startRow = 2;
int startColumn = 1;

// 获取数据的行数和列数
int rowCount = 10;
int columnCount = 3;

// 合并单元格
worksheet.Range(worksheet.Cell(startRow, startColumn), worksheet.Cell(startRow + rowCount - 1, startColumn + columnCount - 1)).Merge();

// 保存Excel文件
workbook.SaveAs("Sample.xlsx");