未在本地计算机上注册“microsoft.ACE.oledb.12.0”提供程序

 System.Data.DataTable dt = new System.Data.DataTable();
            string extension = System.IO.Path.GetExtension(filepath);
            string strConn = "";
            if (filepath.EndsWith(".xls"))
                strConn = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'", filepath);
            else if (filepath.EndsWith(".xlsx"))
                strConn = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 12.0;HDR=Yes;IMEX=1;'", filepath);

            System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(strConn);
            conn.Open();
            System.Data.DataTable dtname = conn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });