如何用C#追加已有excel文件

using OfficeOpenXml;
using System.IO;

public void AppendToExcelFile(string existingFilePath, string newContent)
{
    FileInfo existingFile = new FileInfo(existingFilePath);

    using (ExcelPackage package = new ExcelPackage(existingFile))
    {
        ExcelWorksheet worksheet = package.Workbook.Worksheets[1];

        // 获取已有文件的最后一行
        int lastRow = worksheet.Dimension.End.Row;

        // 追加新内容到下一行
        worksheet.Cells[lastRow + 1, 1].Value = newContent;

        package.Save();
    }
}