.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
david stephan
Gaurav Pal
Post New Web Links

Page.FindControl Causing Null Reference Exception

Posted By:      Posted Date: August 23, 2010    Points: 0   Category :ASP.Net

Hi guys,

I developed a page in VWD 2008 and it works perfectly locally, but when I deployed it on the server every Page.FindControl() call is causing the NullReference Exception "Object reference not set to an instance of an object. " Can anyone help me out? Code is below


Mike Marshall

            For i As Integer = 1 To 10
                If (CType(Page.FindControl("last_" & i), TextBox).Text.Length > 0) Or (CType(Page.FindControl("first_" & i), TextBox).Text.Length > 0) Or (CType(Page.FindControl("dob_" & i), TextBox).Text.Length > 0) Then
                    Dim person_entry(7) As String
                    person_entry(0) = info_list.Count - 1
                    person_entry(1) = CType(Page.FindControl("last_" & i), TextBox).Text
                    person_entry(2) = CType(Page.FindControl("first_" & i), TextBox).Text
                    person_entry(3) = CType(Page.FindControl("dob_" & i), TextBox).Text
                    person_entry(4) = CType(Page.FindControl("appear_" & i), TextBox).Text
                    person_entry(5) = CType(Page.FindControl("mental_" & i), TextBox).Text
                    person_entry(6) = CType(Page.FindControl("behave_" & i), TextB

View Complete Post

More Related Resource Links

Null reference exception

Hi.. I'm trying to retreive values from the textboxes in the footer row of the grid view. My code is : -         con.Open();        SqlCommand com = new SqlCommand("select count(*) from prod", con);        int c = (Int32)com.ExecuteScalar();                if (c == 0)        {            DataTable dt = new DataTable();            DataColumn c1 = new DataColumn("ID");            dt.Columns.Add(c1);            DataColumn c2 = new DataColumn("DESCRIPTION");            dt.Columns.Add(c2);            DataColumn c3 = new DataColumn("QUANTITY");            dt.Columns.Add(c3);            DataColumn c4 = new DataColumn("DATE");          &nbs

Null Reference Exception was not handled by user Object Reference not set to instance of an object

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Security.Principal;using System.Data;using System.Data.SqlClient;using System.Windows;using System.Collections; public partial class Default2 : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {     }    private bool tableCopied = false;    private DataTable originalDataTable;     protected void GridView2_RowDataBound(object sender, GridViewRowEventArgs e)    {         if (e.Row.RowType == DataControlRowType.DataRow)        {            //string sValue = e.Row.Cells[3].Text;             if (!tableCopied)            {                originalDataTable = ((System.Data.DataRowView)e.Row.DataItem).Row.Table.Copy();                ViewState["originalDataTable"] = originalDataTable;      &nbs

Null reference message Custom Error page

how come a Null session value that is called, doesn't get directed to the Custom Error Page?

Null Reference Exception while trying to initialise an Integer array


Hi ,

I am getting System.NullReferenceException:Object reference not set to an instance of an object

while executing the below code..!!

Dim arr() As Integer

Dim g,j As Integer



While g > 0
                arr(j) =0
                g = g - 1
                j = j + 1
End While

Could anybody help me out..!!!

Thanks in advance


I have 2 web pages. First page has a textbox and a button control.

when I enter test and click on the button , system goes to the second page. And in the second page I want to access the Textbox in the first page. When I try to do this I get the following error.

"Object reference not set to an instance of an object. Following is my code :

Dim txt As New TextBox

' Find the server name on the previous page
txt = CType(Page.PreviousPage.FindControl("TextBox2"), TextBox)
If Not IsNothing(txt) Then
Response.Write("[Name Not available]")
End If

I know I could do this with session, but I want to use the Page.PreviousPage.FindControl. Any help is greatly appreciated

reference from menubuttons to text parts in article on the same page


Hi, I'm searching now for hours but couldn't find it.Cry

In my menu i have several buttons which (by a <a href..) should go the a part of an article that is in the same form.

Menu button : What is a database should go to the page default.aspx and in there is an article published.
A part of this article is having a piece of text about "what is a database"

Menu button: how to make a query should go to this same article in the same page but then to the part that is have the piece about the query. The next could be an example of what i'm doing:

    <li><a href="default.aspx ?????>what is a database</a></li>
    <li><a href="default.aspx ?????>what is a query</a></li>

Where my question marks are, there should be a connection to that particular piece of text.
In each article part there is an ID="text1" and the second part id="text2"

How shoudl i do that, Should i use a question mark.
Please give me some guidance how to structure the <li> statement or a pointer where I can read about it.


Dynamic Checkboxlist exception when adding to Panel when using Master Page


In essence, I am creating Dynamic Checkboxlist controls and adding them to a Panel.  It works well when I do not have a Master Page configure to this webpage. Once I have a masterpage congifured.. I get a "Object Reference not set to instance of object" error on the Panel_Control.Controls.Add(Checkboxlistnew) line:

protected void Page_PreInit(object sender, EventArgs e)
        XML OXML = new XML();
        alistChkBoxLabels = OXML.XMLTransform("C:\\Documents and Settings\..\\Config_new.xml", "config_options/check_box/applications/app/@name");
        int count = 1;
        alistCheckisFacility = new ArrayList();
        alIDTracker = new ArrayList();
        while (count <= alistChkBoxLabels.Count)

            Checkboxlistnew = new CheckBoxList();
            Checkboxlistnew.ID = count.ToString();
            Checkboxlistnew.Items.Add(new ListItem(alistChkBoxLabels[count - 1].ToString(), alistChkBoxLabels[count - 1].ToString()));

            String sAppName = alistChkBoxLabels[count - 1].ToString().Trim();

            alistCheckisFacility = OXML.XMLTransform("C:\\Documents and Settings\\Administrator\\My Documents\\Visual Studio 2005\\WebSites\\User_Trial\\Config_new

$.ajax post from asp.net page and __viewstate causing call to fail



Now I know that I won't be sending viewstate and eventvalidation in my ajax calls and that I will only want to send the actual form fields for efficiency purposes but I will need to know the answer to this question, to inform the more junior members of the team and my manager, so if anyone has any answers they are most welcome.

I have a simple form as follows

<form id="form1" runat="server"> 
<p>Field1: <

Getting the exact page causing an error using Server.GetLastError

Using vb.net/asp.net 2005.in the global.asax page in the application error page I am getting the exception information as follows: Dim CurrentException As Exception = Server.GetLastError() Dim ErrorDetails As String = CurrentException.Message.ToString & "<br><br>" & CurrentException.ToString() To find out when there are any exceptions when users are using the system, then the ErrorDetails are being auto-emailed to members on the IT team to help in troubleshooting.The problem is this:  I want to find out what page is the user is on when the exception happens, sometimes the stacktrace does not list the aspx page.  Does anyone know how to get this information?thanksMC

Nested controls in UserControl return null (FindControl)

Hi everyone, I have a very weird issue. I have a UserControl that has some controls inside. I want to refer those controls after, in another postback. But when I try to get them the ".Controls" property of my controls returns null. I'm working on vs2008 Here is the sample code: public partial class MyUserControl : System.Web.UI.UserControl { protected void Page_Load(object sender, EventArgs e) { foreach (Control control in this.Controls) { Response.Write(control.ClientID); } } private void MyTable() { Table table = new Table(); TableRow row = new TableRow(); TableCell cell = new TableCell(); CheckBox check = new CheckBox(); check.ID = "theId"; check.Text = "My Check"; check.AutoPostBack = true; cell.Controls.Add(check); row.Cells.Add(cell); check = new CheckBox(); check.ID = "theOther"; check.AutoPostBack = true; check.Text = "My Other Check"; cell = new TableCell(); cell.Controls.Add(check); row.Cells.Add(cell); table.Rows.Add(row); this.Controls.Add(table); } protected override void Render(HtmlTextWriter writer) { MyTable(); base.Render(writer); } } And in the Default.aspx is like:<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.cs" Inherits="Tester.Default" %> &

FileNotFound exception trying to open a site - Farm.local is Null - x64

  Hello I've created a simple asp.net application to open a site and display the title of the corresponding web. But i'm getting FileNotFoundException while trying to open the site. The same code works perfectly when i run it in a console app. My spec Windows Server 2008 R2 x64 SharePoint 2007 x64 Visual Studio 2005 My target for the asp.net app is set to 'Any CPU'. As far as permissions is considered i've checked that the current identity using which VS2005 hosts the asp.net app has full rights. In fact i've used the same identity for app pools in IIS. As an asp.net web application As a console application Any ideas? Regards NLV Visit SharePoint User group - India

Pass exception details to custom error page.

Hi All, I created a custom error page and update using webApp.UpdateMappedPage(SPWebApplication.SPCustomPage.Error, CustomErrorPage). Its working fine and my custom error page is show if error is occurred. OR We redirect using SPUtility.RedirectToErrorPage("my message"); But I am not able to find my exception details at my custom error page. Is there any way to pass the exception details and other custom information to custom error page?  

Page navigation in a frame throws an exception

I created a very simple WPF project that exhibits the following error. I have no idea how to get of this error. System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.Menu', AncestorLevel='1''. BindingExpression:Path=TemplatedParent; DataItem=null; target element is 'MenuItem' (Name=''); target property is 'CommandTarget' (type 'IInputElement') Steps to reproduce:1. Create a WPF Application project in Visual Studio 2008 (Windows 7)2. Create Page1.xaml <Page x:Class="WpfApplication1.Page1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Page1"> <TextBlock> <Hyperlink NavigateUri="Page2.xaml">Page 2</Hyperlink> </TextBlock> </Page> 3. Create Page2.xaml <Page x:Class="WpfApplication1.Page2" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Page2"> <TextBlock> <Hyperlink NavigateUri="Page1.xaml">Page 1</Hyperlink> </TextBlock> </Page> 4. Add a frame in Window1.xaml <Window x:Class="WpfAppli

Accessing a published web service gives null ref exception. Won't occur in test though?

I have an Asp.net web service that I created using Visual Studio 2005. I can acess the web service in my testenvironment, call methods and return data as expected. If this web service is published to the outside world (Outside of the company firewall), it will return a null reference exception. Does anyone have any idea why this might be happening? The same code is being used,against thesame database. The only difference is that the published website is giving back the null reference exception. If I type in the URL for the web service "https://secure.theSiteGeist.com/wsIndigo.asmx" a list of methods forthe web service is displayed in my browser. Yet if I try and call any methods on the web service I getback the null reference exception. Note that the URL I posted above is not the real name of my web service, but isjust used for reference sake.

how to redirect user to login page if session is null

i have 2 page,1.login.aspx ---  2.welcome.aspxin my login.aspx im storing username into sesssion as below:Session["usernm"] = txtUsername.Text;in my welcome.aspx  pagein page_load event if (Session["usernm"]==null)        {            Response.Redirect("Login.aspx");        }----- here if i manulally paste the url ( http://localhost:4125/Loginado/welcome.aspx) it should go to  login.aspx for user credentialsbut its going directly to welcome.aspx  page.

Variable used before it is assigned value Null reference could

xamount is receiving this message on the last line.  The session is being set in the previous page.  Is there a way to resolve the message or should I just use a previous page postback  Dim subAmt As String = Session("MembType") Dim xamount As String Select Case subAmt Case "0" xamount = "40" Case "1" xamount = "5" Case "2" xamount = "20" Case "3" xamount = "2" End Select post_values.Add("x_amount", xamount)  

UpdatePanel in .Net 4 - Causing Full Page Postbacks

Hi Guys,I've just updated a website from 3.5 to 4.0 and I've noticed that paging controls and command buttons in update panels cause full page postbacks (where they never use to in my 3.5 version).Any ideas why this might be?Cheers,Andrew
ASP.NetWindows Application  .NET Framework  C#  VB.Net  ADO.Net  
Sql Server  SharePoint  Silverlight  Others  All   

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend