private void ExportExcel_Click(object sender, EventArgs e)
{
    Workbook workBook = new       
    Workbook(System.Environment.GetFolderPath(System.Environment.SpecialFolder.Desktop) + "\\" + "1.xlsx");
    workBook.Worksheets.Clear();  //清除預設sheet

    string sheetNames = "Test";

    CreateSheetByName(workBook, new string[] { sheetNames });

    MergeCells(workBook, sheetNames, new int[] { 2, 3, 1, 3 }, 0, new string[] { "合併兩列", "合併三列", "合併一列", "合併三列" });
    MergeCells(workBook, sheetNames, new int[] { 2, 1, 1, 1, 1, 1, 1, 1 }, 1, new string[] { "合併兩列", "合併一列", "合併一列", "合併一列", "合併一列", "合併一列", "合併一列", "合併一列" });

    //SetCellsStyle(workBook,sheetNames);

    List<string[]> values = new List<string[]>()
    {
                new string[]{"1","2","3","4","5","6","7","8","9"},
                new string[]{"1","2","3","4","5","6","7","8","9"},
                new string[]{"1","2","3","4","5","6","7","8","9"},
                new string[]{"1","2","3","4","5","6","7","8","9"}
    };

    ExportDataToExcel(workBook,sheetNames, values, 2);

    Save(workBook);
}

//private void SetCellsStyle(Workbook workBook, string sheetNames)
//{
//    Style style = workBook.CreateStyle();

//    style.HorizontalAlignment = TextAlignmentType.Center;

//    Cells cells = workBook.Worksheets[sheetNames].Cells;
//    cells[0, 0].SetStyle(style);
//    cells[0, 2].SetStyle(style);
//    cells[0, 6].SetStyle(style);
//
}

private void Save(Workbook workBook)
{
    SaveFileDialog SFD = new SaveFileDialog();
    SFD.Filter = "EXCEL檔案(*.xls)|*.xls|EXCEL檔案(*.xlsx)|*.xlsx";
    SFD.FileName = "新建 Microsoft Excel 工作表";
    if (SFD.ShowDialog() == DialogResult.OK)
    {
        workBook.Save(SFD.FileName);
    }
}

private void ExportDataToExcel(Workbook wb , string sheetName, List<string[]> values, int firstRow)
{
    Cells cells = wb.Worksheets[sheetName].Cells;
    for (int i = 0; i < values.Count ; i++)
    {
        string[] tempValue = values[i];

        for (int j = 0; j < tempValue.Length ; j++)
        {
            cells[i + firstRow, j].PutValue(tempValue[j]);
        }
    }
}

private void MergeCells(Workbook wb ,string sheetName, int[] numbers, int firstRow, string[] values)
{
    Cells cells = wb.Worksheets[sheetName].Cells;
    int firstColumn = 0; //起始合併工作列
    for (int i = 0; i < numbers.Length ; i++)
    {
        int number = numbers[i]; //合併的列數集合
        cells.Merge(firstRow, firstColumn, 1, number); //起始行，起始列，合併的行數，合併的列數
        cells[firstRow, firstColumn].PutValue(values[i]);                
              
        //設定列頭居中
        Style style = wb.CreateStyle(); //建立樣式

        style.HorizontalAlignment = TextAlignmentType.Center;

        cells[firstRow, firstColumn].SetStyle(style);  
             
        firstColumn += number; //合併完的起始工作列號
    }
}

private void CreateSheetByName(Workbook wb ,string[] names)
{
    foreach (string sheetName in names)
    {
        if (wb.Worksheets.GetSheetByCodeName(sheetName) == null)
        {
            wb.Worksheets.Add(sheetName);
            AutoFitterOptions options = new AutoFitterOptions();
            options.AutoFitMergedCells = true;
            wb.Worksheets[sheetName].AutoFitRows(options);
        }
    }
}