看看为什么报错啊

[葡萄DDS]

误信息：未将对象引用设置到对象的实例。
这个是为啥啊～以下是代码
DBConnection是一个数据库连接DLL
不知道是什么原因！




using System;
using System.Collections.Generic;
using System.Text;
using DBConnection;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
DBConnection.MSSQLConnection sqlconn = new DBConnection.MSSQLConnection();

try
{
sqlconn.GetConnection().Open();
Console.WriteLine("连接成功");
}
catch (Exception ex)
{
Console.WriteLine("出错了:" + ex.Message);
}
Console.ReadLine();
}
}
}



DBConnection的代码如下


using System;
using System.Collections.Generic;
using System.Text;

namespace DBConnection
{
public class MSSQLConnection
{

private System.Data.SqlClient.SqlConnection conn = null;






/// <summary>
/// 得到数据库连接。
/// </summary>
/// <returns>System.Data.SqlClient.SqlConnection</returns>
public System.Data.SqlClient.SqlConnection GetConnection()
{
return conn;
}


/// <summary>
/// 读取配置文件信息
/// </summary>
/// <returns>System.string</returns>
private string ReadConfig()
{
//读取穿在于临时文件的登录地址信息
string Userid = null;
string pasword = null;
string add = null;
string Linkadd = null;
System.Data.DataSet xmlDataSet = new System.Data.DataSet();
try
{
xmlDataSet.ReadXml(@"Config\LinkAddLog.xml");
foreach (System.Data.DataRow custRow in xmlDataSet.Tables["UserConnection"].Rows)
{
add = custRow["ConnectionAdd"].ToString();
Userid = custRow["ConnectionUserID"].ToString();
pasword = custRow["ConnectionPwd"].ToString();
}
}
catch (Exception ex)
{
throw ex;

}

Linkadd = "server="+add+";user id ="+Userid+";pwd="+pasword+";database=ActualizeManageSystem";

return Linkadd;

}


/// <summary>
/// 生成数据库连接对象
/// </summar>
/// <returns></returns>
private void CreateConnection()
{
try
{
conn = new System.Data.SqlClient.SqlConnection(ReadConfig());
}
catch (System.Data.SqlClient.SqlException ex)
{
throw ex;
}





}
}
}

[moonsliver]

...你在哪里调用了CreateConnection() ？
DBConnection.MSSQLConnection sqlconn = new DBConnection.MSSQLConnection();

try
{
sqlconn.GetConnection().Open();

直接调用构造函数，然后就打开。。但是

public System.Data.SqlClient.SqlConnection GetConnection()
{
return conn;

conn还没有初始化就返回了。。。

[hello_master]

显示未将对象引用设置到对象的实例的话，原因不是连接错误就是数据库不存在咯