C#中excel读取和写入

1.方法一：采用OleDB读取EXCEL文件： 
把EXCEL文件当做一个数据源来进行数据的读取操作，实例如下：

public DataSet ExcelToDS(string Path)
{
string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;" +"Data Source="+ Path +";"+"Extended Properties=Excel 8.0;";
OleDbConnection conn = new OleDbConnection(strConn);
conn.Open();
string strExcel = "";
OleDbDataAdapter myCommand = null;
DataSet ds = null;
strExcel="select * from [sheet1$]";
myCommand = new OleDbDataAdapter(strExcel, strConn);
ds = new DataSet();
myCommand.Fill(ds,"table1");
return ds;
} 

对于EXCEL中的表即sheet([sheet1$])如果不是固定的可以使用下面的方法得到

string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;" +"Data Source="+ Path +";"+"Extended Properties=Excel 8.0;";
OleDbConnection conn = new OleDbConnection(strConn);
DataTable schemaTable = objConn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables,null);
string tableName=schemaTable.Rows[0][2].ToString().Trim();

另外：也可进行写入EXCEL文件，实例如下：

public void DSToExcel(string Path,DataSet oldds)
{
//先得到汇总EXCEL的DataSet 主要目的是获得EXCEL在DataSet中的结构
string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source ="+path1+";Extended Properties=Excel 8.0" ;
OleDbConnection myConn = new OleDbConnection(strCon) ;
string strCom="select * from [Sheet1$]";
myConn.Open ( ) ;
OleDbDataAdapter myCommand = new OleDbDataAdapter ( strCom, myConn ) ;
ystem.Data.OleDb.OleDbCommandBuilder builder=new OleDbCommandBuilder(myCommand);
//QuotePrefix和QuoteSuffix主要是对builder生成InsertComment命令时使用。
builder.QuotePrefix="[";     //获取insert语句中保留字符（起始位置）
builder.QuoteSuffix="]"; //获取insert语句中保留字符（结束位置）
DataSet newds=new DataSet();
myCommand.Fill(newds ,"Table1") ;
for(int i=0;i<oldds.Tables[0].Rows.Count;i++)
{
//在这里不能使用ImportRow方法将一行导入到news中，因为ImportRow将保留原来DataRow的所有设置(DataRowState状态不变)。
   在使用ImportRow后newds内有值，但不能更新到Excel中因为所有导入行的DataRowState!=Added
DataRow nrow=aDataSet.Tables["Table1"].NewRow();
for(int j=0;j<newds.Tables[0].Columns.Count;j++)
{
   nrow[j]=oldds.Tables[0].Rows[i][j];
}
newds.Tables["Table1"].Rows.Add(nrow);
}
myCommand.Update(newds,"Table1");
myConn.Close();
}

2.方法二：引用的com组件：Microsoft.Office.Interop.Excel.dll   读取EXCEL文件 
首先是Excel.dll的获取,将Office安装目录下的Excel.exe文件Copy到DotNet的bin目录下,cmd到该目录下,运行 TlbImp EXCEL.EXE Excel.dll 得到Dll文件。 再在项目中添加引用该dll文件.

    //读取EXCEL的方法   (用范围区域读取数据)
    private void OpenExcel(string strFileName)
    {
        object missing = System.Reflection.Missing.Value;
        Application excel = new Application();//lauch excel application
        if (excel == null)
        {
            Response.Write("<script>alert('Can't access excel')</script>");
        }
        else
        {
            excel.Visible = false; excel.UserControl = true;
            // 以只读的形式打开EXCEL文件
            Workbook wb = excel.Application.Workbooks.Open(strFileName, missing, true, missing, missing, missing,
             missing, missing, missing, true, missing, missing, missing, missing, missing);
            //取得第一个工作薄
            Worksheet ws = (Worksheet)wb.Worksheets.get_Item(1);

            //取得总记录行数   (包括标题列)
            int rowsint = ws.UsedRange.Cells.Rows.Count; //得到行数
            //int columnsint = mySheet.UsedRange.Cells.Columns.Count;//得到列数

            //取得数据范围区域 (不包括标题列)
            Range rng1 = ws.Cells.get_Range("B2", "B" + rowsint);   //item

            Range rng2 = ws.Cells.get_Range("K2", "K" + rowsint); //Customer
            object[,] arryItem= (object[,])rng1.Value2;   //get range's value
            object[,] arryCus = (object[,])rng2.Value2;
            //将新值赋给一个数组
            string[,] arry = new string[rowsint-1, 2];
            for (int i = 1; i <= rowsint-1; i++)
            {
                //Item_Code列
                arry[i - 1, 0] =arryItem[i, 1].ToString();
                //Customer_Name列
                arry[i - 1, 1] = arryCus[i, 1].ToString();
            }
            Response.Write(arry[0, 0] + " / " + arry[0, 1] + "#" + arry[rowsint - 2, 0] + " / " + arry[rowsint - 2, 1]);
        }
         excel.Quit(); excel = null;
        Process[] procs = Process.GetProcessesByName("excel");

        foreach (Process pro in procs)
        {
            pro.Kill();//没有更好的方法,只有杀掉进程
        }
        GC.Collect();
    }

3.方法三：将EXCEL文件转化成CSV（逗号分隔）的文件，用文件流读取(等价就是读取一个txt文本文件)。

           先引用命名空间:using System.Text;和using System.IO;
           FileStream fs = new FileStream("d:\\Customer.csv", FileMode.Open, FileAccess.Read, FileShare.None);
           StreamReader sr = new StreamReader(fs, System.Text.Encoding.GetEncoding(936));

           string str = "";
           string s = Console.ReadLine();
           while (str != null)
           {    str = sr.ReadLine();
                string[] xu = new String[2];
                xu = str.Split(',');
                string ser = xu[0];
                string dse = xu[1];                if (ser == s)
                { Console.WriteLine(dse);break;
                }
           }   sr.Close();

另外也可以将数据库数据导入到一个txt文件，实例如下：

        //txt文件名
        string fn = DateTime.Now.ToString("yyyyMMddHHmmss") + "-" + "PO014" + ".txt";

        OleDbConnection con = new OleDbConnection(conStr);
        con.Open();
        string sql = "select ITEM,REQD_DATE,QTY,PUR_FLG,PO_NUM from TSD_PO014";
       //OleDbCommand mycom = new OleDbCommand("select * from TSD_PO014", mycon);
        //OleDbDataReader myreader = mycom.ExecuteReader(); //也可以用Reader读取数据
        DataSet ds = new DataSet();
        OleDbDataAdapter oda = new OleDbDataAdapter(sql, con);
        oda.Fill(ds, "PO014");
        DataTable dt = ds.Tables[0];

        FileStream fs = new FileStream(Server.MapPath("download/" + fn), FileMode.Create, FileAccess.ReadWrite);
        StreamWriter strmWriter = new StreamWriter(fs);    //存入到文本文件中 

        //把标题写入.txt文件中
        //for (int i = 0; i <dt.Columns.Count;i++)
        //{
        //    strmWriter.Write(dt.Columns[i].ColumnName + " ");
        //}

        foreach (DataRow dr in dt.Rows)
        {
            string str0, str1, str2, str3;
            string str = "|"; //数据用"|"分隔开
            str0 = dr[0].ToString();
            str1 = dr[1].ToString();
            str2 = dr[2].ToString();
            str3 = dr[3].ToString();
            str4 = dr[4].ToString().Trim();
            strmWriter.Write(str0);
            strmWriter.Write(str);
            strmWriter.Write(str1);
            strmWriter.Write(str);
            strmWriter.Write(str2);
            strmWriter.Write(str);
            strmWriter.Write(str3);
            strmWriter.WriteLine(); //换行
        }
        strmWriter.Flush();
        strmWriter.Close();
        if (con.State == ConnectionState.Open)
        {
            con.Close();
        }