System.NullReferenceException:未将对象引用设置到对象的实例 高手赐教! System.NullReferenceException:未将对象引用设置到对象的实例是由于没有对声明的对象实例化 , 或者变量的拼写出错了 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 同意楼上但是看不到sheng.SelectedItem.Text = muqian_sheng 这行,无法具体分析 有错,至少你的con只有Open(),没有Close()。 行 122: jan_muqian_sheng.SelectedItem.Text = wxw_info_muqian_sheng;行 123: jan_muqian_city.SelectedItem.Text = wxw_info_muqian_city ;行 124: jan_hukou_sheng.SelectedItem.Text = wxw_info_hukou_sheng; 源文件: c:\inetpub\wwwroot\job\person\mycenter\resume\resume_basic.aspx 行: 122 堆栈跟踪: [NullReferenceException: 未将对象引用设置到对象的实例。] ASP.resume_basic_aspx.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\job\person\mycenter\resume\resume_basic.aspx:122 System.Web.UI.Control.OnLoad(EventArgs e) +67 System.Web.UI.Control.LoadRecursive() +35 System.Web.UI.Page.ProcessRequestMain() +731 to::jkflyfox我是有些代码没有打. 在从新打一边把,一开始省了点代码:--------------------------------------------最开始想看看用户填了没有!添了呢,我就不用绑定了。就直接附值就行了。jan_muqian_sheng.SelectedItem.Text = wxw_info_muqian_sheng;/之后我才绑定的数据~ DataSet ds = new DataSet(); try { using(OleDbConnection wxw_Connection=new OleDbConnection(wxw_strConnection)) { string wxw_str = "select * from sheng"; OleDbDataAdapter wxw_apr = new OleDbDataAdapter(wxw_str,wxw_Connection); wxw_Connection.Open(); wxw_apr.Fill(ds,"sheng"); jan_muqian_sheng.DataSource = ds.Tables["sheng"]; jan_muqian_sheng.DataValueField="sheng_id"; jan_muqian_sheng.DataTextField="sheng_name"; jan_muqian_sheng.DataBind(); ListItem ll = new ListItem("请选择",null); jan_muqian_sheng.Items.Insert(0,ll); } } catch( OleDbException eo) { er.Text=eo.ToString(); }又根据省给市附值private void jan_muqian_sheng_OnSelectedIndexChanged(object sender, System.EventArgs e) { //目前市的值 DataSet ds = new DataSet(); string wxw_strConnection="Provider=Microsoft.Jet.OLEDB.4.0;"; wxw_strConnection+="Data Source=c:/Inetpub/wwwroot/job/data/mydata.mdb"; try { using(OleDbConnection wxw_Connection=new OleDbConnection(wxw_strConnection)) { string wxw_str = "select city_id,city_name from city where city_sheng_id = '"+jan_muqian_sheng.SelectedItem.Value+"' "; OleDbDataAdapter wxw_apr = new OleDbDataAdapter(wxw_str,wxw_Connection); wxw_Connection.Open(); wxw_apr.Fill(ds,"city"); jan_muqian_city.DataSource = ds.Tables["sheng"]; jan_muqian_city.DataValueField="city_id"; jan_muqian_city.DataTextField="city_name"; jan_muqian_city.DataBind(); ListItem ll = new ListItem("请选择",null); jan_muqian_city.Items.Insert(0,ll); } } catch( OleDbException eo) { er.Text=eo.ToString(); } } 我也有这个问题关注ing http://fason.nease.net/samples/bigarea/ 我用不了javascript的。他的form 中的name只要有有在server.中就不管用了 你把连接字符串 string wxw_str = "select city_id,city_name from city where city_sheng_id = '"+jan_muqian_sheng.SelectedItem.Value+"' ";改成参数形式试试! jan_muqian_sheng是DropDownList?&& wxw_info_muqian_sheng是string?若是那么试试jan_muqian_sheng.Items.FindByText(wxw_info_muqian_sheng).Selected=true; jan_muqian_sheng是DropDownList的话,你看看是不是在代码中有没有声明protected System.Web.UI.WebControls.DropDownList jan_muqian_sheng;不要因为某些原因,把声明搞丢了。 sheng.SelectedItem.Text = muqian_sheng这句旁边的代码上那了啊 DriveInfo問題 Access数据库并发访问的问题,在线等。 保存PictureBox中图片 连接数据库的问题!!急~! 跪求箫心IT乐园论坛注册邀请码 线程插入技术 asp.net 页面上拖动控件,组成一个新的顺序 单击按钮让顺序保存到数据库里 DataSet中如何fill多个表 实现选择界面上的控件问题 C#如何连接一个DDE server ?? C#1.0+ORACLE9i 请问各位,有没有办法用编程的方法生成一个强类型的数据集?
sheng.SelectedItem.Text = muqian_sheng 这行,无法具体分析
行 123: jan_muqian_city.SelectedItem.Text = wxw_info_muqian_city ;
行 124: jan_hukou_sheng.SelectedItem.Text = wxw_info_hukou_sheng;
源文件: c:\inetpub\wwwroot\job\person\mycenter\resume\resume_basic.aspx 行: 122 堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
ASP.resume_basic_aspx.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\job\person\mycenter\resume\resume_basic.aspx:122
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Page.ProcessRequestMain() +731
--------------------------------------------
最开始想看看用户填了没有!添了呢,我就不用绑定了。
就直接附值就行了。
jan_muqian_sheng.SelectedItem.Text = wxw_info_muqian_sheng;
/之后我才绑定的数据~ DataSet ds = new DataSet();
try
{
using(OleDbConnection wxw_Connection=new OleDbConnection(wxw_strConnection))
{
string wxw_str = "select * from sheng";
OleDbDataAdapter wxw_apr = new OleDbDataAdapter(wxw_str,wxw_Connection);
wxw_Connection.Open();
wxw_apr.Fill(ds,"sheng");
jan_muqian_sheng.DataSource = ds.Tables["sheng"];
jan_muqian_sheng.DataValueField="sheng_id";
jan_muqian_sheng.DataTextField="sheng_name";
jan_muqian_sheng.DataBind();
ListItem ll = new ListItem("请选择",null);
jan_muqian_sheng.Items.Insert(0,ll);
}
}
catch( OleDbException eo)
{
er.Text=eo.ToString();
}
又根据省给市附值private void jan_muqian_sheng_OnSelectedIndexChanged(object sender, System.EventArgs e)
{
//目前市的值
DataSet ds = new DataSet();
string wxw_strConnection="Provider=Microsoft.Jet.OLEDB.4.0;";
wxw_strConnection+="Data Source=c:/Inetpub/wwwroot/job/data/mydata.mdb";
try
{
using(OleDbConnection wxw_Connection=new OleDbConnection(wxw_strConnection))
{
string wxw_str = "select city_id,city_name from city where city_sheng_id = '"+jan_muqian_sheng.SelectedItem.Value+"' ";
OleDbDataAdapter wxw_apr = new OleDbDataAdapter(wxw_str,wxw_Connection);
wxw_Connection.Open();
wxw_apr.Fill(ds,"city");
jan_muqian_city.DataSource = ds.Tables["sheng"];
jan_muqian_city.DataValueField="city_id";
jan_muqian_city.DataTextField="city_name";
jan_muqian_city.DataBind();
ListItem ll = new ListItem("请选择",null);
jan_muqian_city.Items.Insert(0,ll);
}
}
catch( OleDbException eo)
{
er.Text=eo.ToString();
}
}
关注ing
javascript的。
他的form 中的name只要有有在server.中就不管用了
jan_muqian_sheng.Items.FindByText(wxw_info_muqian_sheng).Selected=true;
protected System.Web.UI.WebControls.DropDownList jan_muqian_sheng;
不要因为某些原因,把声明搞丢了。