C#高效方法：百万数据3秒内导出到Excel

private void DataTableToCsv(DataTable table, string file)
        {
            StringBuilder titleBuilder = new StringBuilder();
            StringBuilder lineBuilder = new StringBuilder();
            FileStream fs = new FileStream(file, FileMode.OpenOrCreate);
            StreamWriter sw = new StreamWriter(new BufferedStream(fs), System.Text.Encoding.Default);

            for (int i = 0; i < table.Columns.Count; i++)
            {
                titleBuilder.Append(table.Columns[i].ColumnName + "\t"); //栏位：自动跳到下一单元格
            }

            string title = titleBuilder.ToString();
            title = title.Substring(0, title.Length - 1) + "\n";

            sw.Write(title);

            string line = string.Empty;
            foreach (DataRow row in table.Rows)
            {
                for (int i = 0; i < table.Columns.Count; i++)
                {
                    lineBuilder.Append(row[i].ToString().Trim() + "\t"); //内容：自动跳到下一单元格
                }

                line = lineBuilder.ToString();
                line = line.Substring(0, line.Length - 1) + "\n";
                sw.Write(line);

                lineBuilder.Clear();