初学者的疑问！高分救助!

Question

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
namespace MyData
{
    /// <summary>
    /// SqlServerDataBase 的摘要说明
    /// </summary>
    public class DBAccess
    {
        private string strError = null;
        private int intCount = 0;
        public DBAccess()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        /// <summary>
        /// 公开方法DBConn，返回数据库连接
        /// </summary>
        /// <returns></returns>
        public SqlConnection DBconn()
        {
            string strConn = "Server=(local);Database=bole;Uid=sa;pwd=";
            try
            {
                return new SqlConnection(strConn);
            }
            catch (Exception)
            {
                return null;
            }
        }
        /// <summary>
        /// 公开属性ErrorMessage，返回错误信息
        /// </summary>
        public string ErrorMessage
        {
            get
            {
                return strError;
            }
        }        /// <summary>
        /// 根据查询语句从数据库检索数据
        /// </summary>
        /// <param name="strSelect">查询语句</param>
        /// <param name="SqlConn">数据库连接</param>
        /// <returns>有数据则返回DataSet对象，否则返回null</returns>
        public DataSet Select(string SelectString, SqlConnection sqlConn)
        {
            strError = "";
            SqlConnection conn;
            if (sqlConn == null)
            {
                conn = DBconn();
            }
            else
            {
                conn = sqlConn;
            }
            try
            {
                //若数据库连接的当前状态是关闭的，则打开连接
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
                SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
                SqlCommand selectCommand = new SqlCommand(SelectString, conn);
                selectCommand.CommandType = CommandType.Text;
                mySqlDataAdapter.SelectCommand = selectCommand;
                DataSet myDS = new DataSet();
                mySqlDataAdapter.Fill(myDS);
                return myDS;
            }
            catch (Exception e)
            {
                strError = "数据检索失败：" + e.Message;
                return null;
            }
            finally
            {
                if (conn.State != ConnectionState.Closed)
                {
                    conn.Close();
                }
            }
        }
        /// <summary>
        /// 更新数据库
        /// </summary>
        /// <param name="UpdateString">Update Sql语句</param>
        /// <param name="SqlConn">数据库连接</param>
        /// <returns>更新成功返回true</returns>
        public bool Update(string UpdateString, SqlConnection SqlConn)
        {
            return udiDataBase(UpdateString, SqlConn);
        }
        /// <summary>
        /// 从数据库中删除数据
        /// </summary>
        /// <param name="DeleteString">Delete Sql语句</param>
        /// <param name="SqlConn">数据库连接</param>
        /// <returns>删除成功返回true</returns>
        public bool Delete(string DeleteString, SqlConnection SqlConn)
        {
            return udiDataBase(DeleteString, SqlConn);
        }
        /// <summary>
        /// 把数据插入数据库
        /// </summary>
        /// <param name="InsertString">Insert Sql语句</param>
        /// <param name="SqlConn">数据库连接</param>
        /// <returns>插入成功返回true</returns>
        public bool Insert(string InsertString, SqlConnection SqlConn)
        {
            return udiDataBase(InsertString, SqlConn);
        }
        /// <summary>
        /// 根据Sql语句更新数据库
        /// </summary>
        /// <param name="UDIString">更新语句</param>
        /// <param name="SqlConn">数据库连接</param>
        /// <returns>更新成功则返回true</returns>
        public bool udiDataBase(string UDIString, SqlConnection SqlConn)
        {
            strError = "";
            SqlConnection conn;
            if (SqlConn == null)
            {
                conn = DBconn();
            }
            else
            {
                conn = SqlConn;
            }
            try
            {
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
                SqlCommand cmd = new SqlCommand(UDIString, conn);
                cmd.CommandType = CommandType.Text;
                intCount = cmd.ExecuteNonQuery();
                return !(intCount < 1);
            }
            catch (Exception e)
            {
                strError = "更新数据库失败：" + e.Message;
                return false;
            }
            finally
            {
                if (conn.State != ConnectionState.Closed)
                {
                    conn.Close();
                }
            }
        }
    }}
上面是数据库操作类DBAccess.cs
我在页面中想插入记录到数据库，但是老实插不进去，忘高手相助，错在哪里！
页面的代码如下：
protected void Button1_Click(object sender, EventArgs e)
    {
        DBAccess dbaccess = new DBAccess();
        string sql = "Insert Into cluture (culture_name) values('"+TextBox1.Text.Trim()+"')";
        Boolean isOk = dbaccess.Insert(sql,null);
        if (isOk)
        {
            Response.Write("ok");
        }
        else
        {
            Response.Write("error");
        }
    }

Answer 1

你现在的异常信息都被catch捕获了，要先看出什么信息还有，如果你的页面类和DBAccess类不在同一个命名空间的话DBAccess dbaccess = new DBAccess();
需要改为
MyData.DBAccess dbaccess = new MyData.DBAccess();

Answer 2

调试以后，出错是这样的：在 System.Data.SqlClient.SqlException 中第一次偶然出现的“System.Data.dll”类型的异常

Answer 3

写得好复杂。
 不能简单点吗？
public class DataAccess
{
public DataAccess()
{

}    //数据库放在App_Data目录
    private readonly string ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source =|DataDirectory|test.mdb";    public DataSet ReturnDataSet(string cmdText)
    {
        using (OleDbConnection conn = new OleDbConnection(ConnectionString))
        {
            conn.Open();
            using (OleDbDataAdapter oda = new OleDbDataAdapter(cmdText, conn))
            {
                using (DataSet ds = new DataSet())
                {
                    oda.Fill(ds);
                    return ds;
                }
            }
        }
    }    public bool ExecuteNonQuery(string cmdText)
    {
        using (OleDbConnection conn = new OleDbConnection(ConnectionString))
        {
            conn.Open();
            using (OleDbCommand comm = new OleDbCommand(cmdText, conn))
            {
                int i = comm.ExecuteNonQuery();
                if (i > 0)
                {
                    return true;
                }
            }
        }
        return false;
    }
}
-----------------------------------------------------------------------------------------------
string sql = "Insert Into cluture (culture_name) values('"+TextBox1.Text.Trim()+"')";
DataAccess da=new DataAccess();
if(da.ExecuteNonQuery(sql))
{
  //......
}