C# 讀取EXCEL文件的三種經典方法

1.方法一：采用OleDB讀取EXCEL文件：
把EXCEL文件當做一個數據源來進行數據的讀取操作，實例如下：

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; 
} 

對於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：也可進行寫入EXCEL文件，實例如下：

public void DSToExcel(string Path,DataSet oldds) 
{ 
//先得到匯總EXCEL的DataSet 主要目的是獲得EXCEL在DataSet中的結構 
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主要是對builder生成InsertComment命令時使用。 
builder.QuotePrefix="[";     //獲取insert語句中保留字符（起始位置） 
builder.QuoteSuffix="]"; //獲取insert語句中保留字符（結束位置） 
DataSet newds=new DataSet(); 
myCommand.Fill(newds ,"Table1") ; 
for(int i=0;i<oldds.Tables[0].Rows.Count;i++) 
{ 
//在這裡不能使用ImportRow方法將一行導入到news中，因為ImportRow將保留原來DataRow的所有設置(DataRowState狀態不變)。
   在使用ImportRow後newds內有值，但不能更新到Excel中因為所有導入行的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組件：Microsoft.Office.Interop.Excel.dll   讀取EXCEL文件
首先是Excel.dll的獲取,將Office安裝目錄下的Excel.exe文件Copy到DotNet的bin目錄下,cmd到該目錄下,運行 TlbImp EXCEL.EXE Excel.dll 得到Dll文件。 再在項目中添加引用該dll文件.

    //讀取EXCEL的方法   (用范圍區域讀取數據)
    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;
            // 以只讀的形式打開EXCEL文件
            Workbook wb = excel.Application.Workbooks.Open(strFileName, missing, true, missing, missing, missing,
             missing, missing, missing, true, missing, missing, missing, missing, missing);
            //取得第一個工作薄
            Worksheet ws = (Worksheet)wb.Worksheets.get_Item(1);


            //取得總記錄行數   (包括標題列)
            int rowsint = ws.UsedRange.Cells.Rows.Count; //得到行數
            //int columnsint = mySheet.UsedRange.Cells.Columns.Count;//得到列數


            //取得數據范圍區域 (不包括標題列) 
            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;   
            //將新值賦給一個數組
            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();//沒有更好的方法,只有殺掉進程
        }
        GC.Collect();
    }

3.方法三：將EXCEL文件轉化成CSV（逗號分隔）的文件，用文件流讀取(等價就是讀取一個txt文本文件)。

           先引用命名空間: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();

另外也可以將數據庫數據導入到一個txt文件，實例如下：
 

   
        //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讀取數據
        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 


        //把標題寫入.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 = "|"; //數據用"|"分隔開
            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(); //換行
        }
        strmWriter.Flush();
        strmWriter.Close();
        if (con.State == ConnectionState.Open)
        {
            con.Close();
        }