.NET 读取Excel 2007的xlsx文件和读取老的.xls文件是一样的，都是用Oledb读取,仅仅连接字符串不同而已。
读取xlsx 用的是Microsoft.Ace.OleDb.12.0;
具体操作方法如下：
public static DataTable GetExcelToDataTableBySheet(string FileFullPath, string SheetName)
{//string strConn = "Provider=Microsoft.Jet.OleDb.4.0;" + "data source=" + FileFullPath + ";Extended Properties='Excel 8.0; HDR=NO; IMEX=1'"; //此连接只能操作Excel2007之前(.xls)文件string strConn = "Provider=Microsoft.Ace.OleDb.12.0;" + "data source=" + FileFullPath + ";Extended Properties='Excel 12.0; HDR=NO; IMEX=1'"; //此连接可以操作.xls与.xlsx文件OleDbConnection conn = new OleDbConnection(strConn);conn.Open();DataSet ds = new DataSet();OleDbDataAdapter odda = new OleDbDataAdapter(string.Format("SELECT * FROM [{0}]", SheetName), conn);                    //("select * from [Sheet1$]", conn);odda.Fill(ds, SheetName);conn.Close();return ds.Tables[0];}读取Excel文件时，可能一个文件中会有多个Sheet，因此获取Sheet的名称是非常有用的。具体操作方法如下：//根据Excel物理路径获取Excel文件中所有表名public static String[] GetExcelSheetNames(string excelFile)
{OleDbConnection objConn = null;System.Data.DataTable dt = null;try{//string strConn = "Provider=Microsoft.Jet.OleDb.4.0;" + "data source=" + excelFile + ";Extended Properties='Excel 8.0; HDR=NO; IMEX=1'"; //此连接只能操作Excel2007之前(.xls)文件string strConn = "Provider=Microsoft.Ace.OleDb.12.0;" + "data source=" + excelFile + ";Extended Properties='Excel 12.0; HDR=NO; IMEX=1'"; //此连接可以操作.xls与.xlsx文件objConn = new OleDbConnection(strConn);objConn.Open();dt = objConn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);if (dt == null){return null;}String[] excelSheets = new String[dt.Rows.Count];int i = 0;foreach (DataRow row in dt.Rows){excelSheets[i] = row["TABLE_NAME"].ToString();i++;}return excelSheets;}catch{return null;}finally{if (objConn != null){objConn.Close();objConn.Dispose();}if (dt != null){dt.Dispose();}}
}

非常简单就可以读取到文件内容了，.NET就是强大。
命名空间：using System.IO;
返回路径：StreamReader sr = new StreamReader(@"路径", System.Text.Encoding.GetEncoding("GB18030")); //[设置中文编码]
读取文件：textBox1.Text = sr.ReadToEnd();
关闭流：sr.Close();
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