程序老提示未将对象引用设置到对象的实例,找不到原因在那。向高手求教,看问题出在哪,怎么解决?
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;
using System.Text;public partial class Administer_EditArticle : System.Web.UI.Page
{
public SqlConnection sqlcon = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]);
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
fnEditArticle();
}
} public void fnEditArticle()
{
string it = Request["ID"].ToString().Trim();
string strsql = "select * from tb_news where news_id='" + it.ToString().Trim() + "'";
sqlcon.Open();
SqlCommand cmd = new SqlCommand(strsql, sqlcon);
SqlDataReader dr = cmd.ExecuteReader(); if (dr.Read())
{
Article_ID.Value = dr["news_id"].ToString().Trim();
article_Title.Text = dr["news_title"].ToString().Trim();
article_Time.Text = dr["news_time"].ToString().Trim();
txtcontent.Value = dr["news_content"].ToString().Replace("src=\"", "src=\"../");
}
sqlcon.Close();
} protected void btn_AddArticle_Click(object sender, EventArgs e)
{
string it = Request["ID"].ToString().Trim();
string instxt = "update tb_news set news_title='" + article_Title.Text.Trim() + "',news_time='" + article_Time.Text.Trim() + "',news_type='" + article_Type.Text.Trim() + "',news_content='" + txtcontent.Value.Replace("src=\"../", "src=\"") + "' where news_id=" + it.ToString().Trim();
sqlcon.Open();
SqlCommand cmd = new SqlCommand(instxt, sqlcon);
cmd.ExecuteNonQuery();
Response.Redirect("AdminNews.aspx");
}
}
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;
using System.Text;public partial class Administer_EditArticle : System.Web.UI.Page
{
public SqlConnection sqlcon = new SqlConnection(ConfigurationManager.AppSettings["ConnString"]);
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
fnEditArticle();
}
} public void fnEditArticle()
{
string it = Request["ID"].ToString().Trim();
string strsql = "select * from tb_news where news_id='" + it.ToString().Trim() + "'";
sqlcon.Open();
SqlCommand cmd = new SqlCommand(strsql, sqlcon);
SqlDataReader dr = cmd.ExecuteReader(); if (dr.Read())
{
Article_ID.Value = dr["news_id"].ToString().Trim();
article_Title.Text = dr["news_title"].ToString().Trim();
article_Time.Text = dr["news_time"].ToString().Trim();
txtcontent.Value = dr["news_content"].ToString().Replace("src=\"", "src=\"../");
}
sqlcon.Close();
} protected void btn_AddArticle_Click(object sender, EventArgs e)
{
string it = Request["ID"].ToString().Trim();
string instxt = "update tb_news set news_title='" + article_Title.Text.Trim() + "',news_time='" + article_Time.Text.Trim() + "',news_type='" + article_Type.Text.Trim() + "',news_content='" + txtcontent.Value.Replace("src=\"../", "src=\"") + "' where news_id=" + it.ToString().Trim();
sqlcon.Open();
SqlCommand cmd = new SqlCommand(instxt, sqlcon);
cmd.ExecuteNonQuery();
Response.Redirect("AdminNews.aspx");
}
}
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这里存在null数值
所以,出错了
传了吗?
发一下错误提示来看看
try
{
article_Title.Text = dr["news_title"].ToString().Trim();
}
catch
{
article_Title.Text ="";
}
直接这样就行...
当然也可以判断
if (dr["news_title"]!=null )
怎么都行呢
所有行都些上吧
============
这个地方改成
where news_id='" + it.ToString().Trim()+"'";
=========
这里可以是空值的吧,
{
string it = Request["ID"].ToString().Trim();
if(it!=null)
{
string strsql = "select * from tb_news where news_id='" + it.ToString().Trim() + "'";
sqlcon.Open();
SqlCommand cmd = new SqlCommand(strsql, sqlcon);
SqlDataReader dr = cmd.ExecuteReader(); if (dr.Read())
{
Article_ID.Value = dr["news_id"].ToString().Trim();
article_Title.Text = dr["news_title"].ToString().Trim();
article_Time.Text = dr["news_time"].ToString().Trim();
txtcontent.Value = dr["news_content"].ToString().Replace("src=\"", "src=\"../");
}
sqlcon.Close();
}
eles
{}
}
我去测试先...
string a1=null;
this.button1.Text=a1.ToString();
出错, 未将对象引用设置到对象的实例
所以,不能对null进行tostring()
while (sdr.Read())
{
item item = new item();
item.itemID =sdr.IsDBNull(0) ? 0 : sdr.GetInt32(0);
item.itemName = sdr.IsDBNull(1) ? "" : sdr.GetString(1);
item.Summary = sdr.IsDBNull(2) ? "" : sdr.GetString(2);
item.parentID = sdr.IsDBNull(3) ? 0 : sdr.GetInt32(3);
}
//SqlDataReader取到null处理
如12楼那样写吧
=======
楼主,你这个地方没写对啊
应该是:
Value.Replace("src=\"../", "src=\"") + "' where news_id='" + it.ToString().Trim()+"'";
现在问题好像解决了,我运行程序的时候没有再提示错误,我也没有再修改程序的。
就上这一句好使if (dr["news_title"]!=null )