C# Office Excel

// 读取Excel返回DataTable (简略版 不能读取合并格)
// 如果文件第一行是数据不是说明
// 请插入一行 内容随便填 不能为空
public DataTable GetTableFromExcell(string commandText)
        {
            // 连接字符串  (不明白的,请查找 App.config 配置数据库连接字符串)
    string connectionString = System.Configuration.ConfigurationSettings.AppSettings["connectionString"].ToString();       

            SqlConnection sqlConnection = new SqlConnection(connectionString);
            SqlCommand sqlCommand = new SqlCommand(commandText, sqlConnection);

            sqlConnection.Open();

            SqlDataAdapter dataAdapter = new SqlDataAdapter();
            DataTable table = new DataTable();

            dataAdapter.SelectCommand = sqlCommand;
            dataAdapter.Fill(table);

            sqlConnection.Close();

            return table;
        }

public void ExportToExcel(DataTable dt)
        {
            Microsoft.Office.Interop.Excel.Application appexcel = new Microsoft.Office.Interop.Excel.Application();

            SaveFileDialog savefiledialog = new SaveFileDialog();

            System.Reflection.Missing miss = System.Reflection.Missing.Value;

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

            Microsoft.Office.Interop.Excel.Workbook workbookdata;

            Microsoft.Office.Interop.Excel.Worksheet worksheetdata;

            Microsoft.Office.Interop.Excel.Range rangedata;

            //设置对象不可见

            appexcel.Visible = false;

            System.Globalization.CultureInfo currentci = System.Threading.Thread.CurrentThread.CurrentCulture;

            System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-us");

            workbookdata = appexcel.Workbooks.Add(miss);

            worksheetdata = (Microsoft.Office.Interop.Excel.Worksheet)workbookdata.Worksheets.Add(miss, miss, miss, miss);

            //给工作表赋名称

            worksheetdata.Name = "saved";

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

                worksheetdata.Cells[1, i + 1] = dt.Columns[i].ColumnName.ToString();

            }

            //因为第一行已经写了表头，所以所有数据都应该从a2开始

            rangedata = worksheetdata.get_Range("a2", miss);

            Microsoft.Office.Interop.Excel.Range xlrang = null;

            //irowcount为实际行数，最大行

            int irowcount = dt.Rows.Count;

            int iparstedrow = 0, icurrsize = 0;

            //ieachsize为每次写行的数值，可以自己设置

            int ieachsize = 1000;

            //icolumnaccount为实际列数，最大列数

            int icolumnaccount = dt.Columns.Count;

            //在内存中声明一个ieachsize×icolumnaccount的数组，ieachsize是每次最大存储的行数，icolumnaccount就是存储的实际列数

            object[,] objval = new object[ieachsize, icolumnaccount];

            icurrsize = ieachsize;

            while (iparstedrow < irowcount)
            {

                if ((irowcount - iparstedrow) < ieachsize)

                    icurrsize = irowcount - iparstedrow;

                //用for循环给数组赋值

                for (int i = 0; i < icurrsize; i++)
                {

                    for (int j = 0; j < icolumnaccount; j++)

                        objval[i, j] = dt.Rows[i + iparstedrow][j].ToString();

                    System.Windows.Forms.Application.DoEvents();

                }

                string X = "A" + ((int)(iparstedrow + 2)).ToString();

                string col = "";

                if (icolumnaccount <= 26)
                {

                    col = ((char)(‘A‘ + icolumnaccount - 1)).ToString() + ((int)(iparstedrow + icurrsize + 1)).ToString();

                }

                else
                {

                    col = ((char)(‘A‘ + (icolumnaccount / 26 - 1))).ToString() + ((char)(‘A‘ + (icolumnaccount % 26 - 1))).ToString() + ((int)(iparstedrow + icurrsize + 1)).ToString();

                }

                xlrang = worksheetdata.get_Range(X, col);

                // 调用range的value2属性，把内存中的值赋给excel

                xlrang.Value2 = objval;

                iparstedrow = iparstedrow + icurrsize;

            }

            //保存工作表

            System.Runtime.InteropServices.Marshal.ReleaseComObject(xlrang);

            xlrang = null;

            //调用方法关闭excel进程

            appexcel.Visible = true;

        }