I have a problem where an event is firing unexpectedly when the user hits the back button on the browser. Here are the steps.
User clicks button (fires btnNewSurvey_Click)
Browser displays popup window
User closes popup and navigates to a second page from a separate link.
Browser displays second page
User clicks back
btnNewSurvey_Click is fired again (this is the problem)
I was wondering why this is occurring. I've looked into asp.net's page life cycle as well as turning off caching for the page but I cannot reach an explanation.
Let me know if anymore information is required. Thanks!
UPDATE: It seems like the button click event is only getting fired when the user clicks back from chrome
aspx
<asp:Button ID="btnNewSurvey" runat="server" Text="New Survey" OnClick="btnNewSurvey_Click" />
aspx.cs
protected void btnNewSurvey_Click(object sender, EventArgs e)
{
rwScreenList.VisibleOnPageLoad = true;
rwScreenList.Visible = true;
ListBox lbox = rwScreenList.ContentContainer.FindControl("lboxScreenSelection") as ListBox;
((Label)rwScreenList.ContentContainer.FindControl("lblScreenError")).Text = "";
lbox.DataSource = DatabaseFactory.GetScreensForProject(ProjectId);
lbox.DataBind();
}
The problem is that this event is being called when the user hits back from another page.
Problem seems to be in your rwScreenList.VisibleOnPageLoad = true;
As i saw this is telerik property and when you use this property you need to go through certain things.
You can do like this also:
rwScreenList.VisibleOnPageLoad = !Page.IsPostBack;
Please refer below discussion which will help you to resolve from the problem.
http://www.telerik.com/community/forums/aspnet-ajax/window/radwindow-reopening-after-closing-it-in-every-postback.aspx
Related
I am new in ASP.NET and I have a problem..
In my code, btn.Click event does not work for multi buttons what created in tab button control. Can you guys advice me?
Thanks,
<asp:Button Text="TAB MENU" BorderStyle="None" ID="Tab" CssClass="Initial" runat="server" OnClick="Tab_Click" />
<asp:Panel ID="panel1" runat="server" Direction="LeftToRight" HorizontalAlign="Left"></asp:Panel>
protected void Tab_Click(object sender, EventArgs e) {
foreach (...) {
Button btn = new Button();
btn.Click += Button1_Click;
panel1.Controls.Add(btn);
}
}
protected void Button1_Click(object sender, EventArgs e) {
**some code here! but does not work.**
}
Try this
Button btn = new Button();
btn.Click += new RoutedEventHandler(Button1_Click);
panel1.Controls.Add(btn);
Your problem probably lies along the lines of the fact that the button does not exist when the Button1_Click callback is fired... Asp.net webforms is a somewhat leaky abstraction over HTTP, and therefore it's a bit tough to decipher sometimes, but I expect what is happening is that when the postback from your button click occurs, the button doesn't actually EXIST in the control tree, because that button only gets added to the control tree when a tab control is clicked. So because the button does not exist on the postback, webforms doesn't know what to do with the event, so it ignores it...
If your buttons must be created dynamically, consider making them do some javascript to edit some hidden field or something, the value of which you can inspect in the Page_Load method, and then do whatever you want to do functionality-wise with that value.
If they are NOT dynamic, and instead will be the same for each page load (but different for each tab - ie, when the page is loaded, you're drawing some info from a db to decide what buttons to display, but that will not change from postback to postback of the same page), then consider creating the buttons in the Page_Load event instead of inside the event that is raised when the tab is created.
ALTERNATIVELY, since in your comment you suggest that the buttons will be used to open a new window, why not just make the buttons do that client side, ie with javascript window.open commands. Then you don't even need to postback to the server at all...
When I click multiple times on a button that performs a server-side redirect using ASP.NET, thing can get weird. Sometimes I get ViewState errors, other times the page is only partially loaded.
The code for the OnClick event of the button is simple:
HttpContext.Current.Response.Redirect(targetUrl);
If I have something like:
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
Something();
}
}
in the page I'm redirecting to, the Something() function won't be called if the button is pressed more than once in rapid succession.
Is this normal? What could be the cause of these weird issues when pressing buttons multiple times quickly?
Ok as far as i know i could explain the weird result as below:
the first time you click the button, server will do the redirect and since its the first time you hit the page from another page it will not be a postback, but the second time you click the button in the server you will be already redirected and it will see the request as postback because on the server your already on that page, since its redirected you in the first time, at the end you will get the response of the last click which will be a postback in the server.
to avoid this issue, you should make a loading panel appear on the button, or disable the button before you go to the server using javascript.
I have a aspx page that has a Tab control, a few buttons and a User Control on it.
<dx:TabPage Text="Worker Information" Name="tabWorker">
<ContentCollection>
<dx:ContentControl runat="server" SupportsDisabledAttribute="True">
<uc:WorkerInfo runat="server" OnWorkerLoaded="On_Worker_Loaded" OnWorkerUnloaded="On_Worker_Unloaded" />
</dx:ContentControl>
</ContentCollection>
</dx:TabPage>
There are 2 custom events on the user control
public event EventHandler WorkerLoaded;
public event EventHandler WorkerUnloaded;
I have the event handlers in the main aspx page
protected void On_Worker_Loaded(object sender, EventArgs e)
{
btnNext.Enabled = true;
}
protected void On_Worker_Unloaded(object sender, EventArgs e)
{
btnNext.Enabled = false;
}
The On_Worker_Loaded event fires without an issue. I can debug and watch the button become enabled. My problem is when the screen loads the button is still disabled. In my aspx page I disable the button:
<dx:ASPxButton ID="btnNext" runat="server" Text="Next" Theme="MetropolisBlue"
onclick="btnNext_Click" Enabled="false"></dx:ASPxButton>
The 'Next' button is already disabled. This is why you can't really see it. I have framed it with the black outline. When I click that OK button the WorkerLoaded Event fires.
The only other disable is on the On_Worker_Unloaded Event Handler. I don't have it hooked up yet. There is nothing else that causes the button to disable. Any Ideas what I'm missing?
Thanks!
UPDATE
The User Control has a UpdatePanel in it. I don't know if that makes a difference but I thought I would include that. Something else weird happened I noticed. After enabling the button I noticed that if I did a postback the button would be enabled. Does that ring any bells for anyone?
It seems the loaded event is being called before the Enabled=false property is set.
In your debugger check to see whether the Enabled property is already false when the event is called.
Also, what triggers the WorkerLoaded event?
In the end I found a solution that works for me. I put the Next button and the Previous buttons inside their own Update Panel. After I did this everything worked without issue. Thanks for all the ideas and help.
I have some buttons on a web form in my ASP.NET project. The end user has to interact with these buttons like you would with a calculator. My issue is that ever time the end user clicks a button the page is refreshed because of postback. I tried to turn postback off like so:
if (!Page.IsPostBack)
{
protected void btn7_Click(object sender, EventArgs e)
{
const string stringNumber7 = "7";
var text = txtNumber.Text;
text += stringNumber7;
txtNumber.Text = text;
CheckMaxLength();
}
}
But then the click event will not fire. I have tried using images, image buttons, image maps. I can't get the result I want from those object either. I would like to be able to stop postback, but still have my button click event to fire like the would in a windows app. I have see some forums talking using a update panel. I am not sure how to implement an update panel correctly. I am not familiar with AJAX controls.
Does anyone know how I can accomplish want I want to do using an update panel? Or how to stop postback and still fire server side code?
If the botton is invoking local / client side JavaScript, return false within the control event attribute which will cancel the PostBack.
<button onclick="MyMethod();return false;">Click Me</button>
of if you are using a server side control:
<asp:button runat="server" OnClientClick="MyMethod();return false;" />
I've got a gridview/formview, master/detail relationship going on.
When I click a button in my formview (item template), I display an ajaxcontroltoolkit modal popup.
On this popup there is a textbox (several, actually). I want to validate the data in this textbox (at least six digits, so far I'm using a regex validator) before I dismiss the popup.
The validator works, but I can still dismiss the form by clicking OK. What I'd like to do is have the ok button on the popup disabled until the data is good.
I have tried fiddling with some stuff in javascript, but I couldn't make it work, as there seems to be some issues regarding finding controls in a formview.
Any ideas?
Thanks in advance.
Without a postback
You should be able to find a control using the following technique in JavaScript:
$document.getElementById('<%=btnSubmitForm.ClientID%>').disabled = true;
If you're using RegularExpressionValidator, this forum suggests a quick (albeit hacky) way to check and see if your form is valid, without doing a postback:
http://forums.asp.net/t/1114240.aspx
With a postback
You could put the Submit button in its own UpdatePanel, if it isn't already in one, and enable/disable it in the code behind, depending on the value of the validator's IsValid property.
If you're unable to get the enable/disable functionality working, you could simply keep the modal open, so the user can't close it until they enter valid inputs or click Cancel:
protected void BtnSubmitClick(object sender, EventArgs e)
{
if (!regexValidator.IsValid)
{
modalPopupExtender.Show();
}
}