用户代码未处理 System.NullReferenceException Message="未将对象引用设置到对象

jiangxi1111 2012-09-16 11:13:09

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;

public partial class forumadmindetail : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void FormView1_ItemDeleted(object sender, FormViewDeletedEventArgs e)
{
Response.Redirect("~forumadmin.aspx");
}
protected void DataList1_EditCommand(object source, DataListCommandEventArgs e)
{
DataList1.EditItemIndex = e.Item.ItemIndex;
DataList1.DataBind();
}
protected void DataList1_CancelCommand(object source, DataListCommandEventArgs e)
{
DataList1.EditItemIndex = -1;
DataList1.DataBind();
}
protected void DataList1_DeleteCommand(object source, DataListCommandEventArgs e)
{
AccessDataSource2.DeleteParameters["re_id"].DefaultValue = Convert.ToString(DataList1.DataKeys[e.Item.ItemIndex]);
AccessDataSource2.Delete();
DataList1.EditItemIndex = -1;
DataList1.DataBind();
}
protected void DataList1_UpdateCommand(object source, DataListCommandEventArgs e)
{
TextBox TB1 = (TextBox)e.Item.FindControl("TextBox1");
AccessDataSource2.UpdateParameters["re_subjext"].DefaultValue = TB1.Text;
TextBox TB2 = (TextBox)e.Item.FindControl("TextBox2");
AccessDataSource2.UpdateParameters["re_content"].DefaultValue = TB2.Text;
TextBox TB3 = (TextBox)e.Item.FindControl("TextBox3");
AccessDataSource2.UpdateParameters["re_name"].DefaultValue = TB3.Text;
AccessDataSource2.UpdateParameters["re_id"].DefaultValue = Convert.ToString(DataList1.DataKeys[e.Item.ItemIndex]);
AccessDataSource2.Update();
DataList1.EditItemIndex = -1;
DataList1.DataBind();
}
}

每次运行到这句话：AccessDataSource2.UpdateParameters["re_id"].DefaultValue = Convert.ToString(DataList1.DataKeys[e.Item.ItemIndex]); 就会出现：用户代码未处理 System.NullReferenceException Message="未将对象引用设置到对象

请各位多多指教，本人是新手，多谢！

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