Asp.net - Dropdownlist Is Cleared On Page Postback
Apr 8, 2011
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 drop down menu, and based on which item is selected, I call a web service and then dynamically create some text boxes.The first time I drop down the menu and select an item, it works perfectly, and the text boxes are created and populated dynamically. However, the next time I drop down the menu (after the first postback), and select something different..fter the second postback, the original values remain in the textboxes.
How can I make dropdownlist no postback - I have a dropdownlist which I put a code in selected indexchanged - basically for every indexchanged the code will connect to sql and get values then populate textboxes with values.
Here is my code <asp:DropDownList ID="ddlSalesOrg" runat="server" Style="width: 200px;" AutoPostBack="true" />
Obviously when I remove the autopostback="true" - then indexchanged will not function as expected.
I have dropdownlist and set autopostback Property to true.. the problem is that i when i change index of dropdown list Page gets postback. After Completion of Page load index of dropdown goes to 0 automatically.
How can i remain index of dropdownlist after Postback
I'm running into a little problem with a gridview and a dropdownlist. I can get the dropdownlist to load initially, but when it autopostback's it returns with no value. I am populating the dropdownlist in the RowEditing sub. I'm guessing that I must somehow rebind in the RowDataBound sub, but don't know how to go about it. If I try to find the control's SelectedValue I end up with nothing.
VB Code
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not IsPostBack Then
I have a page that contains some dynamically created controls (TextBox and DropDownList). When a postback occurs, the TextBoxes keep their values, but the DropDownLists lose their ListItems. This is quite confusing, since the page level DropDownList also keeps its ListItems.
<%@ Page Language="VB"%> <script runat="server"> Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs)
Let's say I have a DropDownList of product categories and a ListView of products based on the category selection in the DropDownList. When a user visits the page, there is a possibility of conconrency issue as new product belonging to a new category may be added to the inventory as the user is browsing.When the user selects a different category to view(a SelectedIndexChanged event) and causes a postback, I want the DropDownList to update the list of categories to include the new category being concurrently added and at the same time still able to make a change of selected index.
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 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 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?
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]
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 bit of a tricky scenario. It consists of some partial problems for which I have individually found solutions, but I couldn't find anything that makes it all work together smoothly.
-Upon selecting an item in a datagrid, a new page loads with the details regarding that entity. -The entity represents a product that can have any amount of variants (such as a t-shirt's color or size) -I dynamically add dropdownlists to this detail-page that represent these variants (there can be any amount of variants, and each variant can have any amount of different values, each value or combination or values from different variants representing a unique product entity) -Upon selecting a different variant in a dropdown, a delegate is called that will change the session variable to the productId associated with the selected variant and a postback is fired that will reload the page with new data based on this productId
The problem: the postback is fired BEFORE the dropdownlist's (OnSelectedIndexChanged) delegate is called. Since this delegate defines the productId in the session, the new to-be-used productId isn't known at the time of postback.
Result: loading the correct data in the page is always delayed by one postback. Each time I change the selected index of any of the dropdowns, the page is loaded with data based on the session variable that the PREVIOUS OnSelectedIndexChanged delegate of the dropdown set.
I have a LoadData() method that sets the values of all textboxes, fields, labels etc. based on the productId stored in the current session. This method is called on Page_Load. Private Property CurrentProduct As Product Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load LoadData() [Code] .....
It seems that I haven't been completely clear on what does and doesn't apply to this scenario regarding Page Lifecycle.
1) My dropdownlists are added dynamically, which works fine on the first page_load. 2) The content of the dropdownlists is defined by what entity's details i'm loading on the page. 3) What entity's details I'm loading on the page is at first(not-postback) defined by the product I selected in a gridview in the previous page. 4) At postback, this entity is based on a sessionvariable containing the id of the entity. 5) This session variable is defined by what item in the dropdownlist I select. 6) This dropdownlist dissapears after postback since it's not defined on the page, but dynamically. So is the event.
So my guess would go towards some clientside script that stored the selected value before postback, but then I would be clueless on how to get that variable to the server since the logic that retrieves the entity is in the business logic layer which is far away from this page..
I am making my site compatible to all browsers.For that on one page i am selecting the name from dropdownlist and on click of VIEW(button),i want to open a new window .i also want to send the value and text of ddl on new window. all of this i want to do on onClientClick or onClick of button...
I have a window having 2 dropdowmlists(schemename-SN and propertyno-PN) , one chkbox ,one "VIEW" button.SN has options "all" with value=0 and many other options with respctive values.Now,i want the code should behaves as follows:
1.0n window onload, SN must b visible bt PN nt.
2.if i select SN other thn All...the PN shud b visible and if i select "All" ,PN hides.
3.when check box is checked- PN hides,and if it is unchecked- PN visible..
Important:-This whole ddl n chk box are in updatable panel,button is nt in that.I want a browser compatible code so javascript can't b used directly(cz they give problem in mozzila and chrome).Right now, i have done this JavaScript and its is working fine.
function window.onload() { DisableProperty(); }
[code]....
but this code is not browser compatible.here onload,onkeyup and onclick functions are used , but they dont work in other browsers except internet explorer.
I have found a couple of examples on the internet to do this but really struggling to get it working in VB. (Tried a converter but had mixed results) I need the selection options of a Dropdownlist to be populated based upon the differing values in the first dropdown list.
Can anyone help with a releativley simple example in VB? Not fussed if the values are "hard coded" in the script. Or a SQL bit that pulls the data from a table
I have an application in VB.net. I am using the msgbox inside the execution of a loop. Now the message box pops up fine, but when i click on "Ok" in the pop up, the message box
I have the code below which works fine when checkbox at Cell 2 is Checked ie., the date is inserted in Cell 9. Now, when I uncheck Cell 2 I want the Cell 9 to be cleared. Presently, it is not cleared after unchecking. [code]
I'll start off by saying my website has a landing page of http:[url]....
On PageOne.aspx, I have a link to another page: http:[url].....
On PageTwo.aspx, I have an link to the following:
<a href="http:[url].....
The /MyFiles/ directory is actually a virtual directory which points to a file server that holds many other files (PDF, jpeg, doc, etc.).When I navigate to PageTwo.aspx from PageOne.aspx, I can click "back" and still get to PageOne.aspx (my browser history is ok). When I click on the link on PageTwo.aspx, the PDF opens in the same window...then I can click "back" to get back to PageTwo.aspx, but I can't click "back" again to get to PageOne.aspx (it seems like my browser history has been reduced by one page).
I can only imagine that this happens because of the virtual directory since I can't duplicate this problem if the PDF resides on the same server as my .aspx pages. If that is the case, does anyone know how to get around this and still have my PDF reside on the file server (virtual directory)?
I am using ASP.NET. I am not sure what you will call this but I would like text to be displayed in my text box called txtName. So when the form load the text box will have faded text that will say "Required". Then when the user click inside the text box i want the user to place a value inside the text box. Is this possible in ASP.NET? If so, how can this be done????
DataGridViewRow.IsNewRow property is set for the bottom (empty) row. If I set a cell value in the bottom row using DataGridViewCell.Value, IsNewRow remains set. What is the correct way to programatically set a cell value in the botton row to clear IsNewRow?
