[color=800000]SqlConn.Open();  这块代码出现异常 [[/color]ConnectionOpen (Connect()).]SQL Server 不存在或拒绝访问。 

数据库名肯定没错，请教高手如何解决

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;
using System.Web.Caching;
using System.Web.SessionState;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
/// <summary>
///conn 的摘要说明
/// </summary>

    public class conn
    {
        private static string connection = "Provider=SQLOLEDB;Data Source=DFSDFG-LP0WH4KC\\SQLEXPRESS;uid=sa;pwd=181818;Database=ExamOnline;";
        public OleDbConnection SqlConn = new OleDbConnection(connection);
        public conn()
        {
            //
            //TODO: 在此处添加构造函数逻辑
            //
        }
        public void DBopen()
        {
            if (SqlConn.State == ConnectionState.Closed)
            {
                SqlConn.Open();
            }
        }

        public void DBclose()
        {
            if (SqlConn.State == ConnectionState.Open)
            {
                SqlConn.Close();
            }
        }