Server Controls In User Control Are Null When User Control Serves As A Base User Control ?
Jun 4, 2010
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 have a base user control (WC1) which inherits from WebUserControl and a child user control (WC2) which inherits from WC1. I added a textBox and a label to WC1 in vs design view not code behind. But all the server controls that i put in WC1 are null and give null pointer exception.I tried to access textBox and label in different events but the all of them are null.
Steps to reproduce the error:
create a web user control called WC1 by add a new item in VS added a textBox and label server control to WC1 in design view of VS and put code behind: var value = txetBox.Text; created another web user control called WC2 by add a new item in VS and change its base class to WC1 in its code behind create a web page by adding a new item in vs and drag WC2 to the design view of the page run the page then you will see the exception for the codebehind in WC1
[code]....
page:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WC2.ascx.cs" Inherits="WebApplication1.WC2" %>
can web server controls of WC1 be instantiated in this case? or can user control inherit from another user control and web server controls of parent user control be carried to its children without worring the layout?
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 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.
I have a user control (ascx file) that contains an interface for users to change the data retrieved from the db. So, I am displaying data and most of this data can be edited by the user. When the user enters text into a textbox, and clicks "Save Changes", the value they typed in is lost and not persisted to the database. I realize now this is because the SaveChanges button does a postback, and the user control gets reloaded with its original valuesbefore the code within my SaveChanges button gets executed. I'm not sure if there are properties I need to set to save the input data, or if I need to write my own code to do it. What is the generally accepted method to do this? (Also, all of the controls in the ascx file are wrapped in an Update Panel.)
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..
Do we have to do something special to have ASP.NET partial classes aware of controls that are declared in our user control's base classes? The partial classes keep generating declarations for controls in the base class which mean the controls in the base class get hidden and are null.
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..
If a composite server control normally encapsulate styling information inside, it is an example of code encapsulation and modularization. However if css properties are included inside the composite control, it is not ideal for code/styling separation and css code re-use principles. Now which consideration should be the main consideration?
have two user controls on one aspx page. UC1 has a grid which contains a link button column which user clicks. Based on the value of clicked cell, I need to show some data into UC2.How do I pass data from UC1 to UC2? How do I invoke a function of UC2 from UC1?
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">
It's simple to create both user control from the two world : ASP.NET+Razor or MVC 3.0.But i do not known how to consume the user control FROM the razor"_layout.chtml" page.I want to put such thing within the layout page: <uc:MyTag Prop1="" Prop2="" />So i need to declare this directive at top of the layout file : <%@ Register TagPrefix="uc" TagName="MyTag" Src="Controls/Mytag.ascx" %>
I have a progress bar (which is a user control). When user, click a button, this progressbar will get displayed. The issue is ...even if the progressbar is visible, I am able to set focus to other controls in base page. I need to blur the base page...and set focus to user control.
I have a base user control (inherited from System.Web.UI.UserControl)
public delegate void MyEventHandler(object sender, MyEventArgs e); public event MyEventHandler ControlLoaded; //Fire the event from here protected override void OnLoad(EventArgs e) { MyEventArgs cmdEventArgs = new MyEventArgs("somearg"); ControlLoaded(this, cmdEventArgs); }
I have several controls that are derived from this base user control.
On the host ASPX page, I need to subscribe to the ControlLoaded event.
protected void Page_Load(object sender, EventArgs e) { //subscribe to the event //This line DOES NOT WORK as I cannot attach event to a base control - It needs an instance of the user control which I don't have BaseUserControl.ControlLoaded += new MyEventHandler(ControlLoaded); } private void ControlLoaded(object sender, MyEventArgs e) { // some control has been loaded }
I have a user control (uc1) which inherits from uc2. uc2 has a user control (uc3) declared in the markup. I am trying to access uc3 from uc1 but I get NullReferenceException. I thought due to inheritance uc3 would instantiate but looks like I am missing a step.
Clarification:
How does the child user control inherit the markup from the base class? The server controls in the base user control are null in the code behind of the base user control. Why?
I have a user control which contains two text fields each assigned with requiredfield validators this control contains another user control contains say a button .On click of this button i need to validate the fields from the parent control text fields.I try the Page.Validate("ValidationGroup") with Page.IsValid it validates but the error message is not shown .Error message is shown only if i try to validate it from the contains which contains the required field validators ?
Now the weird thing is I have a user control UserControl1 in which I put some JavaScrdipt logic there, and I have another user control UserControl2 and I registered both in the page called Page1.aspx.I would like to call the JavaScript function resided in UserControl1 from UserControl2, however, I got an error saying the function is not defined. I think both user controls are loaded before I use them then I think the JavaScript function can been seen anyway in that page.
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
Is there any way for one user control to raise an event that is handled by another user control without going through the page? I am using Umbraco and do not have access to the page object.
--Edit--
Umbraco has the idea of Macro's (user controls) that it loads into pages. I can't access the page directly as this is part of the framework.
There is a publish subscribe (pubsub) pattern that I know would fit my needs well (2 user controls that need to talk to each other) but am unsure how to hook it up in ASP.Net without the page object.
