读取excel插入到access出错

  if (textBox1.Text.Trim() == "")
            {
                MessageBox.Show("请填写路径！");
                return;
            }
            OleDbConnection conn = new OleDbConnection ("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\ljdata.mdb");
            OleDbConnection conn_Excel = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Jet OLEDB:Database Password=;Extended properties=Excel 5.0;Data Source=" + textBox1.Text);
            OleDbTransaction tran = null;
            try
            {
                //查出EXCEL放入DataTable                conn_Excel.Open();
                string sql = "select * from [Sheet1$]";
                DataTable dt = new DataTable();
                OleDbDataAdapter sda = new OleDbDataAdapter(sql,conn_Excel);
                sda.Fill(dt);                if (dt == null)
                {
                    MessageBox.Show("您导入的文档名字有误！请去掉空格或特殊字符！");
                    return;
                }                //去掉空行
              for (int i = 0; i < dt.Rows.Count; i++)
                {
                    if (dt.Rows[i][0].ToString().Trim() == string.Empty)
                    {
                        dt.Rows.Remove(dt.Rows[i--]);
                    }
                }
                //开始事务
               tran = conn.BeginTransaction();
           
               OleDbCommand cmd = conn.CreateCommand();
                cmd.Transaction = tran;
               for (int i = 0; i < dt.Rows.Count; i++)
                {
                   // string sql_insert = "insert into student(id,name,sex,year,moon,day,class,minzu,shenfenzheng) values ('dt.Rows[i][0].ToString()','dt.Rows[i][1].ToString()','dt.Rows[i][2].ToString()','dt.Rows[i][3].ToString()','dt.Rows[i][4].ToString()','dt.Rows[i][5].ToString()','dt.Rows[i][6].ToString()','dt.Rows[i][7].ToString()','dt.Rows[i][8].ToString()')";
                    string sql_insert = string.Format("insert into student (id,name,sex,year,moon,day,class,minzu,shenfenzheng) values ('1','1','1','1','1','1','1','1','1')");
                     cmd.CommandText = sql_insert;
                     cmd.ExecuteNonQuery();               
               }
                tran.Commit();//提交事务
                MessageBox.Show("导入成功！");
          }
          catch
          {
                MessageBox.Show("导入失败！");
                tran.Rollback();
          }
          finally
          {
                conn.Dispose();
                conn_Excel.Dispose();
          }        }
    }
执行上述语句提示导入失败。没有执行insert语句   好像是执行到红色的语句出的问题。请高手指点一二。非常感谢.