ASP.NET项目连接SQL server数据库问题

总是报：用户未定义sqlexcption！网上说是connectstring 有问题，可我对比了下，连接数据库的字符串一样的，求大神教教我完整的C#连接SQL server的方法和要点，包括web.config的配置等，感激不尽。急求，新手调试C#项目很难受啊！

```private string ExecuteScript(string SQLFile, string scriptName)
{
//TODO: Beef up error reporting code
string ErrorString = string.Empty;
SqlConnection conn = null;

        WriteText(HttpContext.Current.Response, "Installing Script " + scriptName);

        try
        {
            //Open the Schema File, read it and install it.
            using (StreamReader sr = new StreamReader(SQLFile))
            {

                // Create new connection to database
                conn = new SqlConnection(_connectionString);

                conn.Open();

                while (!sr.EndOfStream)
                {
                    StringBuilder sb = new StringBuilder();
                    SqlCommand cmd = conn.CreateCommand();

                    while (!sr.EndOfStream)
                    {
                        string s = sr.ReadLine();
                        if (s != null && s.ToUpper().Trim().Equals("GO"))
                        {
                            break;
                        }

                        sb.AppendLine(s);
                    }

                    // Execute T-SQL against the target database
                    cmd.CommandText = sb.ToString();
                    cmd.CommandTimeout = 600;

                    cmd.ExecuteNonQuery();
                }
                WriteText(HttpContext.Current.Response, " - Success<br>");
            }
        }
        catch
        {
            WriteText(HttpContext.Current.Response, " - Error<br>");
            ErrorString = "Error Installing Schema";
        }
        finally
        {
            //Clos Out the Connection
            if (conn != null)
            {
                try
                {
                    conn.Close();
                    conn.Dispose();
                }
                catch (Exception e)
                {
                    ErrorString = String.Format(@"Could not close the connection.  Error was {0}", e.ToString());
                }
            }

        }
        return ErrorString;

    }

            下面是connectstring：
            <connectionStrings>
<!-- SQL Server Native Client Connection String   -->
<add name="DotNetSCORMDB" connectionString="Data Source=(local);Initial Catalog=DotNetSCORM;Persist Security Info=True;User ID=sa;Password=123" providerName="System.Data.SqlClient" />

<!-- SQL Express Connection String - See readme.txt for setup instructions  
 <add name="DotNetSCORMDB" connectionString="initial catalog=DotNetSCORM;Data Source=.\SQLExpress;Integrated Security=true;AttachDBFileName=|DataDirectory|Club.mdf;User Instance=True" providerName="System.Data.SqlClient"/>
    -->

截图看一下,不能不知道什么错

大兄弟，就是这么错的，你跟我说下C#一般怎么连接数据库的

检查你的实例名是否正确，改用ip或助记名试试，查看网络是否正常

 SqlConnection con = new SqlConnection("server=xxx\\xxxx;database=db_xx;uid=aaa;pwd=bbb;");

试试修改这句话，server设置为你的计算机名称或者ip，给sa设置一个密码

https://support.microsoft.com/zh-cn/kb/914277

sa用户权限设置完 即可

            //连接字符串
            SqlConnection conn = new SqlConnection("server=.;database=DByuekao;uid=sa;pwd=123456;");
            //打开连接
            conn.Open();
        //适配器对象
        SqlDataAdapter sda = new SqlDataAdapter("select h.*,t.TName from House h,HouseType t where h.HouseTypeNo=t.HouseTypeNo", conn);
        //数据集对象
        DataSet ds = new DataSet();
        //向数据及对象中填充数据
        sda.Fill(ds);

                    //关闭连接
        conn.Close();
        //释放资源
        conn.Dispose();

把cs文件发我，我看一下，还有错误信息

是我自己数据库设置问题，看别人代码的确耐心才能出结果。。。