Web Forms :: NullReferenceException On Web User Control?
Oct 27, 2010
As a test, my boss asked me to convert a (not very critical) ASP.NET site from 1.1 to 4.0. Well, it's not extremely difficult and things are going well so far. However, I've hit a small snag. I keep getting a NullReferenceException when I run this code:
m a pretty new developer so I'm not well versed in common ASP.NET problems.As a test, my boss asked me to convert a (not very critical) ASP.NET site from 1.1 to 4.0. Well, it's not extremely difficult and things are going well so far. However, I've hit a small snag. I keep getting a NullReferenceException when I run this code
Context is Null at this point. I am a noob in ASP.NET with regards to Global.asax.cs. This code was written by another developer. EDIT: This is the code with HttpContext...
But I get a NullReferenceException. So I moved the label outside of the table and put it just inside the accordion. The same behavior occurs. Then I gave the accordion panel an ID and did FindControl there, but the same issue occurs.
I don't think I understand fully how ASP.NET does inheritance of controls.I have a user control, ucBase, which has an asp.net label in the ascx file. Code behind references the label and it works fine during run time if the control is not a parent for another user parent.
If I have another user control, ucChild, inheriting from ucBase, the label in ucBase's code is always null. ucChild has no controls in its ascx fileThe server controls (like the label) needs to be declared in the ascx file and not created programmatically.What needs to be done for ucBase to see its own controls when it's a parent user control?
I've got a web site that has a master page and that master page (mpMaster that has a user control ucControl1) which has a sub user control (ucControl2), this user control has a property which accepts a value. Now, I have a page that uses the master page and on this page I have another user control (ucPageControl), I need to find a way of setting the value in ucControl2 from ucPageControl. Is this possible at all?
I am trying to assign user control from another user control ..first time its binding control successfully but when we refresh the data its giving error
saying "Object reference is not set an instance".
how to refresh data from another user control ...
My senerio below :
1 Aspx page
2. User control
calling usercontrol databinding method from aspx page but once it get refreshed ,not allowed to bind it again..
All I would like to be able to do is include one user control within another! Is this possible? I have spent the last hour searching the internet and it seems that I can't find a single thing.
In classic ASP it would be something like: <!--#include file="EditProject.ascx"-->
I tried this but no luck!
Parser Error Message:
There can be only one 'control' directive.
Source Error:
[Code]....
Line 1: <%@ Control Language="VB" AutoEventWireup="false" CodeFile="EditProject.ascx.vb"Line 2: Inherits="Controls_WebUserControl" %>Line 3: <form runat="server">
I need to get the html of a chart control built at runtime. When I call .RenderControl, I get System.NullReferenceException. What could the problem be? Is there another way to go about this (saving as image)? Below is my code.
i hav e1 drop down list where is is to filter shif code , ddl text field contaoins shift desc and value contains shift code.
when i select particular shift description it has to show all the 7 days shift description on text boxes iam using informix database
i have 1 dropdownlist which contains shiftcode & shift decription. where shift code is datavalue filed and desc is dat text field. ddl is conected to sql datasource.
i am getting this error:
Object reference not set to an instance of an object.
I want to use a couple of instances of the same control on a page. The user control is intended to display a list of records in a repeater. The aim is that the second control will show a list excluding the IDs in the first control The control has a number of public properties, including IDsInThisList, and IDstoExclude. The query will exclude the IDs in the second property.
What I would like to do is get the record IDs from the first instance of the control (IDsInThisList), and pass them to the second contro as the IDsToExclude.
I have a test page where I am setting the properties of the controls in code. As you might guess, it's not working! The first control displays the top 3 items, as desired, but the second display the records 1-7, rather than records 4-10 because it is not receiving the IDstoExclude from the first control When I response write the IDstoExclude from the first control in my testpage, the string is empty. (if I do it from within the control, it shows the IDs)
How can I get the controls to fire in order and pass values to each other?
Screen grab of test page + uc and test page code attached
i would like to ask about how can i open user control page when i click a button on parent page, also, can i call parent's method from user control page and then refresh parent page?
i have a web page and inside the page has a placeholder that contains 2 user controls and both visible set to false.
When i click on button1 on the page, it will set the visible of usercontrol1 to true. May i know how do i do it so that when i click on button2 that IS INSIDE usercontrol1, it will hide usercontrol1 from placeholder and set usercontrol2 visible =true?
I have a Master Page and in it I have two user controls,User control 'A' and User control 'B'.
so A and B are in the Same MAster page,I have a Button on Aand when ever i click a button I want to Load Usercontrol B(Call its Page_Load) Method...How will i do that?
this is the code but i get an error at line 'C' --- Null Reference Exception was unhandled
I have a web user control that represents a simple message box. It is used to display simple messages like "Item has been deleted", or "The item was saved successfully".
On the other hand, I have another web user control that represents the item in the form of an editable form (I made this a user control because this is used in two different pages). I want to embed an instance of the message box user control inside the editable form. I am writing this right after the @Control directive:
[Code]....
Instead of using @Register directives, I register the user controls in web.config and so far this has worked just fine.
With the above markup, the project compiles, but whenever I try to navigate to a page that contains this construct, I get an HttpParseException exception. Furthermore, Visual Studio states that the tack w7rc9:MessageBox doesn't represent a known control.
I want to convert windows user control into web user control..I have the usrDataView.cs..I need to convert this file into usrdataview.ascx.can anyonr help me?...how I can convert the file...Is any method is available..
I have an ASP.NET 4.0 application with some simple user controls. The user controls work fine on the design surface (VS.NET 2010), but when they're loaded during application execution, nothing shows up.
Futhermore, the various child controls of the user controls are null when referenced inside the code behind for the user control.
The code behind for the user control executes as expected, but any reference to child controls are null.
It's like ASP.NET is never parsing the ASCX to create the instances of the child controls.