Web Forms :: DropDownList Causing Postback On Change
May 9, 2012
I have 1Dropdownlist 1 button and 1 datalist in my page i bind my datalist in Page_load event that show all my product from my DB ... Users can select their city from DDL click on button and in datalist just show product that are on selected city ...
Problem: when users select PARIS from ddl in datalist show product from selected city and when users want change their city from ddl before their click on button to show that city's product page load again and it show all product again...
I want when users change ddl.selecteditem in datalist show last result of user's selected not the result that i define in page load ... This is my code on page load ...
protected void Page_Load(object sender, EventArgs e) {
if (!IsPostBack) {
DDLcity1.Items.Add(new ListItem("select your city", ""));
BindDropDownList(DDLcity1, "Guidcity", "cityname", "ID");
}
the problem that it is not causing post back on the first selection but on the second, I mean if i select from drop down list first selection no post back on the server,but when i select another item from the list (the second click on a different list item )
I need to know if there is any server-side function/custom-code available to find out the HTML of the entire page which is causing the PostBack.
I don't want to do it using JavaScript/jQuery but instead do it at server side.
A JavaScript workaround that implements it can be found at this link. [URL]
Reason, Why I need it? I am writing some inline javascript in page which performs some vital actions and supposed not to be tampered by user(hacker). So, when a postback occurs, I would like to find out the HTML of entire page (at server) so that I can verify it (I have already generated the hash code for entire HTML while rendering the page to check it on consecutive postbacks) for non-tamering and then process further.
This is the reason why I need a way to find out the HTML of the page causing the PostBack.
I have an issue that seems to only happen on my production server. I show or hide table rows whenever the buttons are clicked. However, when I do a postback on the checkbox, all of the rows become visible and the textbox stays empty. It works correctly on my test server and local workstation, just not in production.
Here is the markup...
[Code]....
Here is the code behind...
[Code]....
Here are the unexpected results whenever I check the chkShow2 checkbox... I am guessing this is a configuration issue on the server.
I'm having trouble with an image button I create via c# in an event causing page validation to occur on postback. The CausesValidation attribute is set to false at time of creation in the event. I also wire up the Click event in the page_init with postback so not to loose the event handler if the page posts another way. Here is the code I'm using in the click event of a Button. I've also tried to enable and disable viewstate for the button with no luck. What am I missing here that continues to fire page validation in the Click of this imagebutton?
I have the following tabpanel (it actually contains a bit more content, but that content doesnt influence my issue):
[code]....
When I remote the MaskedEditExtender and MaskedEditValidator, it doesnt show that (undesired) behaviour anymore.Is there something special these controls do that cause them to refresh? Is there a workaround for this?
Below is the sample code on using the update panel. The page just has a button and a label. On button click it updates the label with the server time. Though the label is inside the update panel the page goes for a complete postback. in understanding why it is behaving like that. I tried the options of Updatemode, using different script references nothing seems working for this simple application.
I've got a template field in a gridview that contains just a simple button...
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Administration.aspx.cs" Inherits="Administration" %> <%@ Register TagPrefix="ajaxToolkit" Namespace="AjaxControlToolkit" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
[Code]....
Whenever I click the button I get the error...
Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
I've found a decent amount of articles referencing this issue, including a couple on SO, for example...
[URL]
and...
[URL]
I might just be misunderstanding, but as far as I can tell they don't really help me. How do I get this to go away without setting enableEventValidation="false"?
I have searched high and low on this error, but my problem stems back to which control is causing this problem. In theory the problem starts when someone goes to a specific tab and clicks a button to download a PDF file. After doing that if I use a dropdownlist the error pops up.I have checked the code etc. just cannot figure out which control is triggering the error. I can identify the control that is the problem?
I have a modalpopupextender and I want to be able to update the information without causing a postback and having to re-show the modal, normally I use an updatepanel and this is working in most cases but I have an issue with a repeater where the ItemCommand has been set but clicking the button does not fire anything, unless I set the repeater as a trigger but this then does postback and I lose where I am. Not the usability I want to provide.
I have a link button inside a template field of a gridview. The gridview is wrapped in an update panel. I want the link button to fire an async postback but it always fires a full postback. Why is this?
This is a similar problem to the one described in the link below. However, I have tried doing a RegisterAsyncPostbackControl in the gridview databound, but this did not work.
I have put several buttons and panels in my update panel. I also have a script manager on that page. now when I click on any of the buttons then the functionality is working fine but problem is that the complete page gets reloaded witha a flick, instead of updating the update panel only. I have set the "children as trigger" property of update panel "true".
I am having issue with my ModalPopUpExtender's OKControlID. I have a button inside an update panel that should do AsyncPostBack. The button works fine and runs server side code but it causes full page postback. How do I solve this issue? I want the 'OK' button inside the modalpopup to call the serverside code and update Label control 'label3' without causing the page flash. Given below is my code;
MarkUp:
<html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>Next Gen Web Browser</title> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.3.2.js" type="text/javascript"></script>
I have a user control with linkbuttons (used for paging) and a repeater inside an update panel. The paging works correctly, but is causing a full page postback every time I click through to the next page.
The update panel looks like this:
[code]....
So far, I have tried adding an async postback trigger for the user control, which does cause an async postback but does not update the rest of the text in the update panel. In otherwords, the async postback occurs and the next page shows up, but the original text in the repeater is there as well just below it.
I have also confirmed that I have IDS set on my linkbuttons, since that can trigger a full postback inside an update panel.
I have tried changing the update panel mode (Always, Conditional, ChildrenAsTriggers, etc.).
None of it makes a difference - the only thing that actually causes an async postback is to use the trigger, but then the rest of the content in the update panel is not updated, so I get duplicate content.
I had use a combox to let user select staff name and then it will automatically retrive the responsible recommending officer and approving officer to display in other 2 dropdownlist.
my code works fine but when user select staff name each time, the page will reload once to refresh the dropdownlist.
user complaint and don't want the page reload every time, how can i disable the postback? I need to use ajax?
Using ASP.NET VB, I have a form with some text boxes and a Gridview. If a user clicks the Edit button on a row in the gridview, and then tries to submit the form with a row still in edit mode on the Gridview, this error is generated -
"Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. "
In my default.aspx page I have a PlaceHolder control within an UpdatePanel. In this placeholder control I will dynamically load a web user control, which is just a form with a submit button. On this user control, I have the form within an update panel and I have the "Submit" button's Click Event added to the triggers.
When I submit the form, the UpdatePanel on the web user control nor the update panel on the default.aspx page are capturing the post back, thus causing a full post back which refreshes my page.
how to capture this post so its rendered in Ajax and not a full post back?
This would be a simple one for me if I was binding this dynamically. I don't think it's necessary to have a code behind for only 4 or so values. Anyways here is my ddl.
[Code]....
The problem is that when a user selects a value and it postbacks my ddl resets to the first value. How do I prevent this?
I have 5 dropdpwnlist in asp.net page.. the 5th dropdwpnlist will show data based on 4th dropdownlist. and 4th dropdwpnlist will show data based on 3rd dropdownlist. and 3rd dropdwpnlist will show data based on 2nd dropdownlist. and 2th dropdwpnlist will show data based on 1st dropdownlist... All dropdownlist has auto postback=true.. so it cause postaback each time.. i want to avoid postback coz it refresh all page again and again and shows data.. coz my aplication is in hosting server..
I created a dropdwonlist and add colours to the items. But the colours will lose after the postback. After googled, I knew it is because the attributes specified for the dropdownlist were not saved in ViewState and also found the code to Overriding SaveViewState() and LoadViewState(object) from [URL]
But after I copy the code to my web application to create a new class, there are so many error massages. I have spend two days to find the solution, without much success.
I have a situation where i want to postback and redirect the user to the diffterent page wherever the user selects something from dropdown list. If the user presses the back button the in the browser the dropdownlist should be in the default state. i have already tried this code
protected void ddl_SelectedIndexChanged(object sender,Eventargs e) { int selecteditem = int.Parse(ddl4.SelectedItem.Value.ToString()); ddl.ClearSelection( ddl.Dispose(); //Even tried ddl.selectedindex = -1 ; //dosome postback i.e redirecting the user depeneding upon the value in selecteditem }
