//创建一个Excel.Application的新进程

Microsoft.Office.Interop.Excel.Application app = new Application();

if (app == null) return;

app.Visible = false;

app.UserControl = true;

Workbooks workbooks = app.Workbooks;

_Workbook workbook = workbooks.Add(XlWBATemplate.xlWBATWorksheet);//这里的Add方法里的参数就相当于继承了一个空模板(暂这样理解吧)

Sheets sheets = workbook.Worksheets;

_Worksheet worksheet = (_Worksheet)sheets.get_Item(1);

if (worksheet == null) return;

DataSet ds = Convert_StringToDataSet(str);

System.Data.DataTable dt = ds.Tables[0];

string bidName = "";

int projNum = 0;

for (int i = 0; i < dt.Rows.Count; i++)

{

    projNum++;

    bidName = dt.Rows[i]["BigFactorClassName"].ToString();

    worksheet.Cells[1 + i, 1] = i + 1;

    worksheet.Cells[1 + i, 3] = dt.Rows[i]["SmallFactorClassName"];

    worksheet.Cells[1 + i, 4] = dt.Rows[i]["FactorClassName"];

    if (i == 0)//如果是第一行，就直接写了

    {

        worksheet.Cells[1 + i, 2] = dt.Rows[i]["BigFactorClassName"];

    }

    else if (bidName == dt.Rows[i - 1]["BigFactorClassName"].ToString())//此行与上一行时行比较，如果相等就不写值

    {

        worksheet.get_Range(worksheet.Cells[i + 1, 2], worksheet.Cells[i, 2]).Merge(Type.Missing);

    }

    else

    {

        worksheet.Cells[1 + i, 2] = dt.Rows[i]["BigFactorClassName"];

    }

}

worksheet.Name = "导出Excel测试1";

string tick = DateTime.Now.Ticks.ToString();

string save_path = "C:\\Users\\Administrator\\Desktop\\" + tick + ".xls";

workbook.SaveAs(save_path, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

Response.Write("<script>alert('导出成功！')</script>");