Reading 'Checked' Property Of Dynamic CheckBox On Page Postback
Dec 29, 2009
How can I check the 'Checked' property of a dynamically-created checkbox during the Page_Load subroutine? Basically, I have a VB.NET page that creates some table rows dynamically, based on a number selected by the user. So, for example, if the user selects "3" from a dropdown list, the page posts back and creates three table rows. Each row contains a couple of textboxes, a dropdown list, and a checkbox (which are all .NET form controls rather than plain HTML controls, I should point out).Typically, the user would enter a few details into the form controls, and click the 'Submit' button, after which the page iterates through each row, and inserts the data into a SQL Server table.But if the user ticks the checkbox for that row, this signifies that the page is to ignore that row, and NOT insert that row of data into the database when the user clicks 'Submit'. This works well, but there is a problem. If the user clicks 'Submit' and some of the values entered into the form controls are invalid (so, for example, the user didn't enter their name) then the page won't submit the data, and instead, shows an error to the user informing them of the values they need to change. But if the user creates three rows, for example, but decides to "ignore" the third row (by ticking the checkbox) then when the page posts back, finds some invalid entries, and re-shows the form to the user to allow them to correct any errors, I'd rather the page didn't render the third row altogether. After all, they chose to create three rows originally, but then decided that they only needed two. So it makes sense that the third row is not recreated.
But what seemed to happen was that objCheckbox.Checked was always returning False, even when the checkbox was ticked. Once the page had loaded, the table rows had rendered again, and the tick was present in the checkbox, so it's not like the value was lost on postback. But at the point I check whether the checkbox is ticked, it always returns False, rendering a table row that the user doesn't need.Does anyone know how to get round this problem? I've read lots of articles about the .NET ViewState, and the page lifecycle, but I've yet to find a solution that works. I simply need to be able to check if a checkbox is ticked before re-creating some dynamic controls. [code] But then I basically found out that you can't override a protected member with a public one.
I have a project in VB.NET which is working fine which essentially has a Datagrid that has a TemplateColumn included which is a column of Checkboxes. The code to declare the datagrid is here...
everything you see sbove is working perfectly fine...in the sense that when I click one of the checkboxes, the page_load fires, the gridItemDataBound fires on DataBind() and when all is done, the checkbox retains the value that the user clicked the checkbox.
With all this exact same code converted to C#....the events all fire in the same order, but the checkbox selected value always clears...
I have unlimited asp.net checkboxes to my webpage .How to insert checkbox checked value to textbox without autopostback.I i check checkbox1 and checkbox2 then in textbox it appear as 1,2 ...and after when i uncheck checkbox1 then in textbox the value would be 2.and if i uncheck checkbox1 and checkbox2 then value in textbox is blank
I am working on a little project and am having some issues with a checkbox. I am adding a number of checkboxes to an ASP table via code by adding rows and columns dynamically. This all works fine except for when I go to check them based on loading a preexisting record. For some reason some of the checkboxes are getting set to TRUE when the new row is added to the table. [Code]
I have a question, I can't really find the answer...Basically I have 2 FormsIn form number 1 I have 2 pictureboxes. I want to create a checkbox in form2 that says if checkbox 1 is checked then show picture 1 in form 1
I created an item user_control that has a textbox, button, etc. which will intentionally collect the total quantity of items the user wants.
I dynamically create a few intances of user_control on page_load. If you click the add button for the item quantity it will add to a session variable. however when the user enters a different quantity in the textbox and clicks the add button the total is of the original value of the textbox.
How to get the value the the user has typed in to the textbox to add to total???
I've create a stripped down example below: [UserControl] [Page] [CodeBehind]
UserControl... <%@ Control Language="vb" AutoEventWireup="false" CodeBehind="BomItem.ascx.vb" Inherits="DynamicUserControl.BomItem" %> <style type="text/css">
I'm dynamically loading User Controls into a div, which I need to preserve on postback in order to call a Save method once the user is done editing them. The div and all the User Controls have the EnableViewState = True.
So... the controls load fine, but I can't find a way to preserver them on postback, I can't reload them because the user has already input data into the usercontrol (which is what I need to save).
P.S. I tried adding them to a list and then adding the list to the ViewState, but I haven't been able to properly serialize the control. I implemented ISerializable for the userControl's code behind but then it says the ASCX is mot marked as serializable with
Type 'ASP.controls_userControlType_ascx' in Assembly 'App_Web_pn5vxhpw, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.
I have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem Public ID As Integer Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
I've got a handful of dynamic controls populating an ASP page, with VB.NET in the back-end.What I need is when the user changes the .TEXT value of a textbox and the page posts back, the .TEXT value of a Table Cell changes to reflect that change (it multiplies the value of the textbox by the value of another cell).But a Table Cell can't be set to AutoPostBack, and I can't for the life of me figure out how to programmatically refresh the page (force a postback) in the TextChanged event for the textbox.
I have a page with three radio buttons and a calendar usercontrol. The radio buttons have autopostback and depending on which one you click it should change the calendar availabilities based on the selected index.The problem is that the page load of the calendar is executing first before the selected index change (where I am setting the needed id).
i have 5 checkboxes in webform and textbox1... when i search the record using the date specified in textbox1 when i enter 11-Dec-2010 in Textbox1 and click on submit button then checkbox1, checkbox2, and checkbox3 will be disabled and unchecked .....
I have a FormView bound to a SqlDataSource on my page. One of the controls on the FormView is a DropDownList, which gets populated on Page_Load (it's being populated with a list of file names from a specific folder).
Everything goes well when the page first loads. I am able to view the list of files, select one and, upon hitting the "save" button, store the correct filename in the database. However, when the page refreshes after the post back - the DropDownList is empty.
I have a form with a update panel. This posts the form and validates it. Returning a errorMessage string of any invalid field such as "Field xyz is a required field, Field abc needs to be a quantity" When I enter incorrect date it posts back fine and displays the text in a div at the bottom of the page which the update panel is aimed at to update. (and only this it should be changing)This works but the second time I hit say (say i enter invalid data twice) the Complete form will disappear leaving me with just the banner of the site and the error message that is returned.
I am working with adding up user's scores based on their checks in a CheckBoxList. Every time a user checks a box, a value, X, is added to the overall score. When a user unchecks a box, a value, X, is subtracted from the overall score. No problems here.
The problem that I am having is that using the AutoPostback option in the CheckBoxList properties forces the page to load back to the top instead of staying where the user was situated, which means that they have to keep scrolling down after each check/uncheck. Is there a way to prevent this?
I have some DataGridView code written in vb.net. (Nothing is attached to a datasource.)The 4th column is a checkbox cell.How do I detect if that checkBox is checked or unchecked?This code strangely reports TRUE or FALSE at random times. It even turns ON the checkbox in rows other than the row I clicked in. (Huh?)
Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick Dim whichGrid As DataGridView = CType(sender, DataGridView)
[code].....
I've tried countless other methods... none seem to actually get the checkbox ON/OFF value in vb.net.
I have a aspx page, in that page i have an Iframe. In the Iframe i do some stuff in code behind and when it is done I would like to do a postback from the aspx. In other words, Is it possible to do a postback programatically from the code behind of the iframe to the parent page?
Whenever I change the value of MyTextBox and press MySubmitButton, the select method of MyObjectDataSource is invoked and everything works OK. But if I change the value of any of my check boxes (without changing the value of MyTextBox) and press MySubmitButton, the select method is not invoked, thus the "MyObjectDataSource_Selecting" event doesn't take place and I get the same results as before.
One way I found to work around this was to explicitly invoke MyGridView.DataBind method whenever MySubmitButton was clicked. Is this the best way to handle these type of parameters? What I am afraid is that this may cause the select method to be called twice making the page slower.
After the download dialogue opens I need a series of changes to happen on the page, but I have noticed all the code after this code will not run. Anyone know how I can make the page changes occur AND get the download dialogue to pop up?
I have grouped some checkbox in GroupBox1, 2, 3 respectively. Now I want to know the tag value ( I am using a TAG property to assign a some value to radio button ) of check box which is checked in either of the groupboxes.
I've got a simple Visual Basic 2008 Express Edition form which looks like this:[link Screenshot of simple form][1]I need some help with a skeleton script, which checks to see if each checkbox is checked or not. I've got a set of Word templates which all contain a macro.And I want to run the macro of each template, if the template exists.[code] know this pseudocode isn't correct at all, because I'm kind of a beginner, and designer over a programmer. But I've just started learning and I know this is pretty basic.it's just getting an overview of the logics in programming. And I think that getting to learn how to do this will help me with other things as well.
i'm trying to set several checkbox to be checked based on retrieved value from database.So when i load the data,if the value is the same with checkbox name,then it will be checked.Is it possible to do that?
when I clicked the send button it would work, but if you tried to hit enter it would just do a postback to the same page. Yesterday I thought I finally got it so it would work on chrome (it has been working just fine on firefox, but breaking on chrome/safari and it is an app for the iphone). But, even though I finally got it so it would change pages, it is now displaying an error. I narrowed down the cause to a postback that is being called right before the postback I want is being sent which is then cancelled. I assume the cancelled postback is blank because the problem I was having was the page would do a blank postback.[code]
I have a datagridview with a checkbox column.i want to check whether checkbox is checked or not.If the checkbox is selected it should output as "True" in messagebox and if checkbox is not selected it should giving me a message "False".
I have the function below which I call onload, I want to be able to check the checkbox (chkactive) if the ProjectStatus is set to True, how can I do that please.[code]
and when a user clicks on cell4, it's supposed to add the value of "Holiday" to my database and all of the data from that line. What's happening is that I can't even click on the checkbox.