Question

“/”应用程序中的服务器错误 未将对象引用设置到对象的实例

说明：执行当时web请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以用及代码中导致错误的出处的详细信息。
异常详细信息：System.NullReferenceException：未将对象引用 设置到对象的实例。
源错误：
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace RiYanOffice.NodeEvent.Check
{
public partial class OrderList : System.Web.UI.Page
{
private readonly RiYanOffice.BLL.OrderInfo bll = new RiYanOffice.BLL.OrderInfo();
private static string strNK = "";
private static string strOrderList = "";
protected void Page_Load(object sender, EventArgs e)
{
strNK = Request.QueryString["NK"].ToString();///出现错误
strOrderList = Request.QueryString["OrderList"].ToString();
//strNK = "9";
//strOrderList = "8";
Session["strWhere"] = " and a.OrderID in (" + strOrderList + ")";
if (!Page.IsPostBack)
{
BindData();
}
}

Answer 1

一般'未将对象引用设置到对象的实例'是
1.实例对象为空
2.或者向你这样 调用空的 Request.QueryString
解决办法
1。为空判断
if (Request.QueryString["NK"] != null)
{}
2.付默认值。

Answer 2

断点跟踪一下，看哪儿没有取到值

Answer 3

这样改一下:

if (Request.QueryString["NK"] != null)
{
strNK = Request.QueryString["NK"].ToString();
}
strOrderList = Request.QueryString["OrderList"].ToString();
//strNK = "9";
//strOrderList = "8";
Session["strWhere"] = " and a.OrderID in (" + strOrderList + ")";
if (!Page.IsPostBack)
{
BindData();
}