连接Access数据库

web.config添加配置

  <connectionStrings>
    <add name="connStr" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|Example.mdb" providerName="System.Data.OleDb"/>
  </connectionStrings>

App_Data文件夹中放

 App_Start文件夹放帮助类：

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.OleDb;
/// <summary>
/// 数据库操作类
/// </summary>
public class Common
{
    private static OleDbConnection conn = new OleDbConnection();
    private static OleDbCommand comm = new OleDbCommand();
    public Common()
    { 
        
    }
    /// <summary>
    /// 打开连接
    /// </summary>
    private static void openConnection()
    {
        if (conn.State == ConnectionState.Closed)
        {
            try
            {
                conn.ConnectionString =System.Web.Configuration.WebConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
                comm.Connection = conn;
                conn.Open();
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
        }
    }
    /// <summary>
    /// 关闭连接
    /// </summary>
    private static void closeConnection()
    {
        if (conn.State == ConnectionState.Open)
        {
            conn.Close();
        }
        conn.Dispose();
        comm.Dispose();
    }
    /// <summary>
    /// 执行一条sql语句
    /// </summary>
    /// <param name="sqlStr">sql语句</param>
    public static void ExecuteSql(string sqlStr)
    {
        try
        {
            openConnection();
            comm.CommandType = CommandType.Text;
            comm.CommandText = sqlStr;
            comm.ExecuteNonQuery();
        }
        catch (Exception e)
        {
            throw new Exception(e.Message);
        }
        finally
        {
            closeConnection();
        }
    }
    /// <summary>
    /// 返回一个数据集
    /// </summary>
    /// <param name="sqlStr">sql语句</param>
    /// <returns></returns>
    public static DataSet dataSet(string sqlStr)
    {
        OleDbDataAdapter da = new OleDbDataAdapter();
        DataSet ds = new DataSet();
        try
        {
            openConnection();
            comm.CommandType = CommandType.Text;
            comm.CommandText = sqlStr;
            da.SelectCommand = comm;
            da.Fill(ds);
        }
        catch(Exception e)
        {
            throw new Exception(e.Message);
        }
        finally
        {
            closeConnection();
        }
        return ds;
    }
    /// <summary>
    /// 返回一个数据视图
    /// </summary>
    /// <param name="sqlStr">sql语句</param>
    /// <returns></returns>
    public static DataView dataView(string sqlStr)
    {
        OleDbDataAdapter da = new OleDbDataAdapter();
        DataView dv = new DataView();
        DataSet ds = new DataSet();
        try
        {
            openConnection();
            comm.CommandType = CommandType.Text;
            comm.CommandText = sqlStr;
            da.SelectCommand = comm;
            da.Fill(ds);
            dv = ds.Tables[0].DefaultView;
        }
        catch (Exception e)
        {
            throw new Exception(e.Message);
        }
        finally
        {
            closeConnection();
        }
        return dv;
    }
}

或用这个帮助类：

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.OleDb;
 
    /// <summary>
    /// DBHelper 的摘要说明
    /// </summary>
    public class DBHelper
    {
        public static string connStr = System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
        public DBHelper()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

        public DataSet GetDataSet(string sql)
        {
            OleDbConnection conn = new OleDbConnection(connStr);
            OleDbDataAdapter da = new OleDbDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds);
            return ds;
        }

        public bool ExecSql(string sql)
        {
            bool IsSucceed = false;
            OleDbConnection conn = new OleDbConnection(connStr);
            conn.Open();
            OleDbCommand cmd = new OleDbCommand(sql, conn);
            try
            {
                cmd.ExecuteNonQuery();
                conn.Close();
                IsSucceed = true;
            }
            catch (Exception e)
            {
                throw e;
            }
            return IsSucceed;
        }

        public OleDbDataReader GetReader(string sqlStr)
        {
            OleDbDataReader dr = null;
            OleDbConnection conn = new OleDbConnection(connStr);
            OleDbCommand cmd = new OleDbCommand(sqlStr, conn);
            conn.Open();
            try
            {
                dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch
            {
                conn.Close();
            }
            return dr;
        }

        public int GetExexScalar(string sqlStr)
        {
            int ret = 0;
            OleDbConnection conn = new OleDbConnection(connStr);
            OleDbCommand cmd = new OleDbCommand(sqlStr, conn);
            conn.Open();
            try
            {
                ret = (int)cmd.ExecuteScalar();
            }
            finally
            {
                conn.Close();
            }
            return ret;
        }

        public string GetExexScalarString(string sqlStr)
        {
            string ret = "";
            OleDbConnection conn = new OleDbConnection(connStr);
            OleDbCommand cmd = new OleDbCommand(sqlStr, conn);
            conn.Open();
            try
            {
                ret = (string)cmd.ExecuteScalar();
            }
            finally
            {
                conn.Close();
            }
            return ret;
        }
    }

test:

        protected string GetTopNews()
        {
            StringBuilder sb = new StringBuilder();
            string sqlStr = "select * from Employee"; 
            DataTable dt = Common.dataSet(sqlStr).Tables[0];
//  DataTable dt = new DBHelper().GetDataSet(sqlStr).Tables[0];
            if (dt.Rows.Count > 0)
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    sb.Append("<li>" + dt.Rows[i]["ID"] + ":" + dt.Rows[i]["EmpAddress"] + "</li>");
                }
            }
            return sb.ToString();
        }