无需在.net core 3.1中打开即可将excel文件保存为csv格式

using OfficeOpenXml;
using System.IO;

public void ConvertExcelToCsv(string excelFilePath, string csvFilePath)
{
    // 打开Excel文件
    using (var package = new ExcelPackage(new FileInfo(excelFilePath)))
    {
        // 获取第一个工作表
        var worksheet = package.Workbook.Worksheets[0];

        // 创建CSV文件流
        using (var csvStream = new StreamWriter(csvFilePath))
        {
            // 写入CSV文件头
            for (int col = 1; col <= worksheet.Dimension.End.Column; col++)
            {
                csvStream.Write(worksheet.Cells[1, col].Value);
                if (col < worksheet.Dimension.End.Column)
                {
                    csvStream.Write(",");
                }
            }
            csvStream.WriteLine();

            // 写入CSV文件内容
            for (int row = 2; row <= worksheet.Dimension.End.Row; row++)
            {
                for (int col = 1; col <= worksheet.Dimension.End.Column; col++)
                {
                    csvStream.Write(worksheet.Cells[row, col].Value);
                    if (col < worksheet.Dimension.End.Column)
                    {
                        csvStream.Write(",");
                    }
                }
                csvStream.WriteLine();
            }
        }
    }
}