C#怎样用excel.dll读取excel文件

public DataTable ReadExcelToTable(string filepath)        {            string excelfilePath = Server.MapPath("Excel/Excel.xls");            Excel.Application myExcel = new Excel.ApplicationClass();            Excel.Workbooks myBooks = myExcel.Application.Workbooks;            object oMissing = System.Reflection.Missing.Value;             Excel.Workbook myBook = myBooks.Open(excelfilePath, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing);             //Excel.Workbook myBook = myExcel.Workbooks[1];            int sheetint = myBook.Worksheets.Count;//能得到sheet的数量             Excel.Worksheet mySheet = (Excel.Worksheet)myBook.Worksheets[1];            int rowsint = mySheet.UsedRange.Cells.Rows.Count; //得到行数            int columnsint = mySheet.UsedRange.Cells.Columns.Count;//得到列数            System.Data.DataTable dt = new System.Data.DataTable("mytable");            for (int i = 1; i < columnsint; i++)            {                dt.Columns.Add("F" + i.ToString(), System.Type.GetType("System.String"));            }            DataSet myDs = new DataSet();            myDs.Tables.Add(dt);            DataRow myRow;            myDs.Clear();             for (int i = 2; i < rowsint; i++) //第一行为标题，不读取            {                myRow = myDs.Tables["mytable"].NewRow();                for (int j = 1; j < columnsint; j++)                {                     Excel.Range r = (Excel.Range)mySheet.Cells[i, j];                    string strValue = r.Text.ToString();                    string aa = strValue;                    string columnname = "F" + j.ToString();                    myRow[columnname] = strValue;                 }                myDs.Tables["mytable"].Rows.Add(myRow);            }             return myDs.Tables["mytable"];        }