asp.net--自定义数据库连接类（OLEDB）

来源：互联网发布：vscode 联想输入编辑：程序博客网时间：2024/05/17 01:11

类库代码superConn.cs代码如下：

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Data.OleDb;namespace 练习{    public class superConn    {        private OleDbConnection cnn;        private OleDbCommand cmd;        private OleDbDataReader datar;        public superConn(string mdbFileName){            string _path = "~\\App_Data\\" + mdbFileName;            string str_conn = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source="                + System.Web.HttpContext.Current.Server.MapPath(_path);//调用MapPath的完整命名空间            cnn = new OleDbConnection(str_conn);        }        //打开连接        public void open() {            cnn.Open();        }        //关闭连接        public void close() {            cnn.Close();        }        public OleDbDataReader getDateReader(string _sql) {            cmd = new OleDbCommand(_sql, cnn);            datar = cmd.ExecuteReader();            return datar;                }    }}

.aspx代码如下：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="测试自定义数据库连接类.aspx.cs" Inherits="练习.测试自定义数据库连接类" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server">    <title></title></head><body>    <form id="form1" runat="server">    <div>            <asp:Button ID="Button1" runat="server" Text="Test" onclick="Button1_Click" />        </div>    </form></body></html>

.aspx.cs代码如下：

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data.OleDb;namespace 练习{    public partial class 测试自定义数据库连接类 : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {        }        protected void Button1_Click(object sender, EventArgs e)        {            superConn  mycnn= new superConn("data.mdb");            mycnn.open();               string _sql="SELECT* FROM T_IMGS";            OleDbDataReader dr=mycnn.getDateReader(_sql);            while (dr.Read()) {                Response.Write(dr["img_url"].ToString()+"<br>");             }            mycnn.close();                    }    }}

测试运行时出现如下错误：

<span style="color:#ff0000;">“/”应用程序中的服务器错误。在 ConnectionString 中未指定 OLE DB 提供程序。示例为:“Provider=SQLOLEDB;”。说明: 执行当前 Web 请求期间，出现未经处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。 异常详细信息: System.ArgumentException: 在 ConnectionString 中未指定 OLE DB 提供程序。示例为:“Provider=SQLOLEDB;”。源错误: 行 16:             string str_conn = "Provide=Microsoft.Jet.OLEDB.4.0; Data Source="行 17:                 + System.Web.HttpContext.Current.Server.MapPath(_path);//调用MapPath的完整命名空间行 18:             cnn = new OleDbConnection(str_conn);    行 19:     }行 20:         //打开连接源文件: C:\Users\Administrator\documents\visual studio 2010\Projects\练习\练习\superConn.cs    行: 18 堆栈跟踪: [ArgumentException: 在 ConnectionString 中未指定 OLE DB 提供程序。示例为:“Provider=SQLOLEDB;”。]   System.Data.OleDb.OleDbConnectionString.ValidateProvider(String progid) +1044395   System.Data.OleDb.OleDbConnectionString.ValidateConnectionString(String connectionString) +252   System.Data.OleDb.OleDbConnectionString..ctor(String connectionString, Boolean validate) +563   System.Data.OleDb.OleDbConnectionFactory.CreateConnectionOptions(String connectionString, DbConnectionOptions previous) +36   System.Data.ProviderBase.DbConnectionFactory.GetConnectionPoolGroup(String connectionString, DbConnectionPoolGroupOptions poolOptions, DbConnectionOptions& userConnectionOptions) +150   System.Data.OleDb.OleDbConnection.ConnectionString_Set(String value) +59   System.Data.OleDb.OleDbConnection.set_ConnectionString(String value) +4   System.Data.OleDb.OleDbConnection..ctor(String connectionString) +26   练习.superConn..ctor(String mdbFileName) in C:\Users\Administrator\documents\visual studio 2010\Projects\练习\练习\superConn.cs:18   练习.测试自定义数据库连接类.Button1_Click(Object sender, EventArgs e) in C:\Users\Administrator\documents\visual studio 2010\Projects\练习\练习\测试自定义数据库连接类.aspx.cs:20   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5563</span>

根据错误提示进行代码检查，发现如下拼写错误：

修改后调试，得到如下正确结果：

0 0