I am having an ASP.NET page with one Asp.net button control and a normal html link (anchor tage) I want to invoke the postbackl event of asp.net button control when someone clicks on the link.
I used the below code
<a href="javascript:myFunction();" class="checkout" ></a>
<asp:Button ID="btnCheckout" runat="server" Visible="false"
onclick="btnCheckout_Click" />
and in my javascript i have
function myFunction()
{
var strname;
strname = "Test";
__doPostBack('btnCheckout','OnClick');
}
But when runnin gthis , i am getting an error like __doPostBack is undefined
Can any one tell me why it is ?
Thanks in advance
This anyway wouldn't have worked. When you make your .NET control invisible by using 'Visible="false"' it isn't rendered, that means not available at the client.
Back to your question.
1- Where is myFunction defined? Between the tag?
2- Are there more .NET controls on the page? If there aren't any other .NET controls, .NET doesn't add all the scripts that are required for postbacks and stuff.
Why not do the following (based on TheVillageIdiot answer):
<asp:LinkButton ID="lbtnCheckout" runat="server" CausesValidation="false" OnClick="lbtnCheckout_Click" CssClass="checkout" />
With the above example you don't need the fake button and make it invisble. You still can do your postback. Way more cleaner approach I would say.
First of all I tried your code and also not get anything like __doPostBack, then I added another button on the page which was visible but it was all the same. Then I added a LinkButton and got __doPostBack method. You can do post back from javascript but then EventValidation is problem, as it does not allow this kind of thing. I had to use the following to overcome it and it worked:
protected override void Render(HtmlTextWriter writer)
{
ClientScript.RegisterForEventValidation(
new PostBackOptions(btnCheckout, "OnClick"));
base.Render(writer);
}
I think I'm bit incoherent in answering so I'll mark it as wiki :)
Related
I have an asp button that looks like this:
Default.aspx
<asp:button id="button1" runat="server" Text="clickme" onclick="function" />
Default.aspx.cs
protected void function(object sender EventArgs e)
{
// Do some calculation
}
However, whenever I press the button, the entire page gets refreshed. I have looked on this site and found many solutions, but none of them really works for my project. Here are some of the suggested solutions:
set onclick="return false;" // but then how do I run the function in the code-behind?
use !IsPostBack in Page_Load // but the page still refreshes completely. I don't want Page_Load to be called at all.
Disable AutoEventWireup. // making this true or false doesn't make a difference.
Does anyone have a solution to this, or is it really impossible?
I would place the control inside of an Update panel.
To do so, you would also need a script manager above it, so something like this:
<asp:ScriptManager runat="server" ID="sm">
</asp:ScriptManager>
<asp:updatepanel runat="server">
<ContentTemplate>
<asp:button id="button1" runat="server" Text="clickme" onclick="function" />
</ContentTemplate>
</asp:updatepanel>
if a control inside the update panel does a postback, it will only reload the part of the page inside of the upate panel.Here is a link you may find useful from the MSDN site.
I think there is a fundamental misunderstanding here of how ASP.Net works.
When a user first requests your page, an instance of your Page class is created. The ASP.Net framework runs through the page lifecycle with this page instance in order to generate html. The html response is then sent to the user's browser. When the browser receives the response it renders the page for the user. Here's the key: by the time rendering is complete, your page class instance was probably already collected by the .Net garbage collector. It's gone, never to be seen again.
From here on out, everything your page does that needs to run on the server, including your method, is the result of an entirely new http request from the browser. The user clicks the button, a new http request is posted to the web server, the entire page lifecycle runs again, from beginning to end, with a brand new instance of the page class, and an entirely new response is sent to the browser to be re-rendered from scratch. That's how ASP.Net (and pretty much any other web-based technology) works at its core.
Fortunately, there are some things you can do to get around this. One option is to put most of your current Page_Load code into an if (!IsPostBack) { } block. Another option is to set up your method with the [WebMethod] attribute and make an ajax request to the method from the button. Other options include calling web services from custom javascript and ASP.Net UpdatePanel controls.
What works best will depend on what other things are on the page that user might have changed.
That is normal behavior for asp.net, you are actually causing a postback of the the page in order for the associated event to be called on the server.
I would suggest working with update panels but if you just need something to happen on the backend without it causing any major change on the web page, I would use jquery and a web service. The main reason for me is that update panels create huge viewstate objects.
Have a look here for asp.net ajax : http://www.asp.net/ajax
And here for an example of jquery and wcf : http://www.codeproject.com/Articles/132809/Calling-WCF-Services-using-jQuery
I have a similar problem. this answer helps me a lot. in your asp button.<asp:button id="button1" runat="server" Text="clickme" OnClientClick="return SomeMethod();" /> and in the SomeMethod which is a js method do your logic like manipulating your page then return false as the mentioned answer suggest.
I have a form that currently uses an control to submit a form. Everything works perfectly. So now the new requirement is for the "submit' button to be a link. Changing it to a LinkButton control, without changing a SINGLE other thing, breaks the validation.
There is a bit too much code to post in a SO question and I know there's a bit of a lack of detail here, but is there any reason why a LinkButton wouldn't fire ASP.NET validation the same way a Button control would? In theory, they should both operate exactly the same, no?
The current submit button:
<asp:Button ID="btnSubmit" TabIndex="9" Text="Send" ValidationGroup="Forward" runat="server" />
The new submit button:
<asp:LinkButton ID="btnSubmit" TabIndex="9" Text="Send" ValidationGroup="Forward" runat="server" />
The Link button should fires the validation the same way a normal button does, my concerns in your case would be the following:
make sure these is nothing in the server side code stopping this.
make sure in the javascript code there is nothing stopping the "
ASP.NET controls that fire validation has a property called CauseValidation
Be sure all controls should fire validation, has this property set to True
Add attribute CauseValidation="True" to your control but if you want to fire this at particular line at code behind you can use validate the form by the following code:
FormID.Validate();
I know this is old but it has never answered. Did your validator have a "controlTovalidate"? Currently it would appear as if the validator was not firing but in reality it is. It just does not have anything that it is 'watching'. Hope if anyone reaches this thread that this helps even if it is just a little bit.
I was unable to determine the cause of this issue but was able to solve it:
I set the CausesValidation="false" and added at the top of the onclick event this.Validate(linkButton.ValidationGroup) this allows the event to get to the code behind and validation to occur.
Let say I got the following button : <asp:Button ID="btnSearch" runat="server" /> and the following button event handler :
Protected Sub btnSearch_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSearch.Click
How, with JQuery, can I call the button event handler ?
What I mean is that I don't want the page to refresh, so it's kind of Ajax call. I don't want to simulate the click but that on click the button event handler is call.
$("#<%= btnSearch.ClientID %>").click();
UPDATE
There are many ways of doing this asynchronously. You could have your button be set up as a trigger for an UpdatePanel, and then my original answer would still work. I wouldn't do that, but that's because I hate UpdatePanels.
You could create a page method in your code behind class, like this:
[WebMethod]
public static void Search()
{
// Do search
}
and in your ScriptManager (you'll have to add one if you don't have it), enable page methods.
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true" />
Then, you don't even need a server control for your button. Just use a plain old button.
<input type="button" onclick="search()" value="Search" />
// Then in javascript...
function search()
{
PageMethods.Search(function(result)
{
// deal with search result here (this is the success handler)
});
}
Or you could call your page method directly from jquery, as shown by this Encosia article.
Or, you could have a completely separate service, not part of your code behind, that encapsulates your search logic, and you could call it any number of ways.
Since you've updated your question, you're question isn't really about how to execute your button's click handler, it's about how to do an async operation. And it's a little vague. There are a million ways to do that.
I would advise staying very far away from Microsoft's AJAX as it is really heavy. jQuery has a really easy implementation and if you just need a simple async callback pagemethods are the way to go.
Also to save your self some hassle check out the "json2" library for json serialization of everything. I haven't had it break on me yet and I have had to serialize some fairly complex objects.
link text
I have a page that uses a master page, several RequiredFieldValidators, and the Web Toolkit autocomplete extender. The following code only shows the bare minimum of the page:
<%# Page Language="C#"
AutoEventWireup="true"
CodeFile="Login.aspx.cs"
MasterPageFile="~/master.master"
Inherits="Login" %>
<asp:Content id="Content1"
contentplaceholderid="ContentPlaceHolder1"
runat="server">
<asp:UpdatePanel ID="pnlUpdate" runat="server">
<ContentTemplate>
<div>
<asp:ImageButton class="submitButton"
imageurl="images/button_submit.gif"
id="btnSubmit"
runat="server"
onclick="btnSubmit_ServerClick"/>
</div>
</ContentTemplate>
</asp:UpdatePanel>
</asp:Content>
Code-behind:
protected void btnSubmit_ServerClick
(object sender, ImageClickEventArgs e)
{
//breakpoint here does not get hit
}
The <form runat="server"> tag is in the master page. The code above does not fire the onclick event. If I get rid of the master page and add a form tag to the page, it works. Is the form tag in the master page not supported, or is this supposed to work somehow?
alt text http://digitalcopy.warnerbros.com/images/mainmenu.gif?provider=00079&disc=03403AAA-1D20-47F2-91FA-5EE632832659
You can also check if your ImageButton does not trigger validation. If it does set its CausesValidation property to false (of course if it makes sense).
I had a similar issue (different scenario). I used Page.RegisterRequiresRaiseEvent(ImageButton) and my onclick event started to fire. Why I needed to do that? I don't know.
My solution was to set the ImageButton's CausesValidation to false.
I have a similar issue with the image button and found the root cause. You are using
"ib.ID = i + ":" + j;"
as the ID of the ImageButton, the ":" is illegal name to use, as you are creating it programmatically, ASP.NET allows it to be created.
At runtime, if you look at the HTML source of the page, you will see the special characters are either ignored or replaced with "_". So the page is unable to find the correct control, thus the event won't fire. Try changing the name with plain text, the event will fire.
ib.ID = i + ":" + j;
should be changed to
ib.ID = i.toString()+":"+j.toString();
If it still doesn't work try making use of the StringBuilder to buildup the ID and assign it later to ib.ID property
This is solution that worked for me
If you are binding through data bound controls then use OnCommand attr instead of OnClick attr
You have to have the control in a form runat=server somewhere, it can be in the Master page or the .aspx file. Double check that the master page form tag is runat=server
AutoEventWireup is the property that allows the syntax you are using. Double check the setting in the Master Page, WebForm and it can also be set in the web.config.
if that doesnt work, you can always explicilty code it (which I prefer)
<script runat=server>
protected override void OnInit(EventArgs e)
{
btnSubmit.Click += delegate(object sender, EventArgs e1)
{
};
base.OnInit(e);
}
</script>
UpdatePanel can mess with server side events being raised also, so try it without the UpdatePanel. And I am sure you have a ScriptManager in the Master Page
From the code you supplied, you seem to be missing the <asp:scriptmanager> from your page. You must do one of the following:
Have the <asp:scriptmanagerproxy> on the page and the <asp:scriptmanager> on the master page.
Have <asp:scriptmanager> on your page and no <asp:scriptmanager> on the master page.
Personally, I recommend having the <form> tag on the master page, but that's personal preference.
You can always try taking out the UpdatePanel and seeing if it works. I usually start without the UpdatePanel, get everything working the way I want and then add in the UpdatePanel and debug anything that causes.
The form in the MasterPage works for me so the ScriptManager/ScriptManagerProxy mentioned by #Keltex might be an issue, though I forget them sometimes and usually get away with it.
With the UpdatePanel the button's click event will be handled via Javascript, so you might grab FireBug or equivalent (depending on browser) and follow through what actually is happening. Is it tripping on the validation and you don't see it? Is there a JS error somewhere (the Control Toolkit isn't perfect always)? Is the page actually posting back at all and just not hitting the event handler?
On my webpage i am creating imagebuttons dynamically inside a table that is contained by an updatepanel. The buttons are created by this code:
for (int i = 0; i < 15; i++)
{
TableRow tr = new TableRow();
for (int j = 0; j < 20; j++)
{
TableCell tc = new TableCell();
ImageButton ib = new ImageButton();
ib.Click += new ImageClickEventHandler(ImageButton1_Click);
ib.ImageUrl = "../img/defaultCell.jpg";
ib.ID = i + ":" + j;
tc.Controls.Add(ib);
tc.Width = 25;
tc.Height = 25;
tr.Cells.Add(tc);
}
GameTable.Rows.Add(tr);
}
}
The image buttons will not trigger click events. HOWEVER, if the line 'ib.ID = ...' is commented out, they do! That single alternation seems to fix all the issues.
I have no idea why.
If anyone can explain this, and also tell me how to trigger events keeping the ability to set button id's, i'd be much thankful
I think it may have something to do with the fact your re-assigning the id's after creating & assigning the event handler?
Do you even need to assign the id's? - Surely this is done for you anyway? - True removing the 'ib.ID = i + ":" + j;'
Make sure you use OnClick rather than onClick
Your update panel could be messing with the postback. Try it without the UpdatePanel and see if that is the culprit.
I had the same problem that OnClick event of ImageButton was not firing. But the actual problem was, at form level, I had onSubmit="return false;"
I was facing the same issue, where I was dynamically creating an ImageButton and click of that event was not triggering. hence, i created the Image button in if (IsPostBack) . Now it is working fine. And even if the page gets refresh, the ImageButton will be retained.
I've just solved a similar issue where OutputCache was enabled. When changing from asp:ImageButton to asp:Button, the event is correctly fired. Probably asp:ImageButton has some bug with OutputCache.
After none of the above suggestions worked for me, I did one more try by calling the button creation in OnInit(). This fixed my issue and now the OnClick event is firing.
I've a simple asp.net page (framework 3.5) and an UpdatePanel with a series of dropdownlist I want to populate asyncronously. All works fine in all major browsers (Opera, Safari, IE6, IE7, FF3), but not in Chrome.
Chrome seems to ignore the SelectedIndexChanged event who had to make the asynch request.
Anyone knows a simple workaround to this?
Thanks!
EDIT: More Informations
As I say to Adam Lassek, the updatepanel refresh after the click to an asp:Button inside of it, but it doesn't work with the dropdown's SelectedIndexChanged event.
The updatepanel is set like:
<asp:UpdatePanel ID="updPanel" runat="server" UpdateMode="Always" ChildrenAsTriggers="true">
without Triggers specified, and the dropdows have sets AutoPostBack="true"
UPDATE: (and retagging)
After a few attempts I discover that it isn't a problem of the UpdatePanel, but it seems that the AutoPostback of dropdowns doesn't work properly, even in pages without ScriptManager and UpdatePanel...
I'm sure that it is a problem concerning only this project, because if I start a new WebSite from scratch and replicate the structure of this, works fine in Chrome...
I'm trying to remove step by step all the other things in the original project to find exactly what's the problem.
If anyone has some ideas in meantime....
There is a known incompatibility with Ajax.NET and Chrome & Safari 3.
Small, quick tests can be deceptive because it will appear to work fine with the existing Ajax.NET library as is. This is because it manages to perform the first Ajax request and fails when that ends, so only when you try to perform the second Ajax action will you notice it has failed. If you put an UpdateProgress control on your page, you'll notice that after the first request your UpdateProgress control won't disapppear.
Luckily, there is an answer!
Recently there was a great post put up detailing what to do which you can find here:
http://blog.turlov.com/2009/01/aspnet-ajax-compatibility-patch-for.html
The general gist of it is that both Chrome and Safari 3 report themselves as WebKit in their userAgent strings.
You need to add a little bit of javascript in to aid the Ajax.NET framework in recognising WebKit based browsers that looks like the following:
if (typeof(Sys.Browser.WebKit) == "undefined") {
Sys.Browser.WebKit = {};
}
if (navigator.userAgent.indexOf("WebKit/") > -1 ) {
Sys.Browser.agent = Sys.Browser.WebKit;
Sys.Browser.version =
parseFloat(navigator.userAgent.match(/WebKit\/(\d+(\.\d+)?)/)[1]);
Sys.Browser.name = "WebKit";
}
You need to add that to a javascript file and reference it in your ScriptManager:
<asp:ScriptManager ID="ScriptManager1" runat="server">
<Scripts>
<asp:ScriptReference Path="~/assets/javascript/WebKit.js" />
</Scripts>
</asp:ScriptManager>
Note that you can keep the WebKit.js in an assembly and reference that by using a ScriptReference tag similar to this:
<asp:ScriptReference Assembly="Scripts" Name="Scripts.webkit.js" />
Once you've done all that, if at all possible stop using WebForms and Ajax.NET and use MVC and jQuery :)
This happens because MicrosoftAjax.js does browser detection, and it's incorrectly detecting Chrome as Safari. In order to fix this, you need to make the following changes:
Add a new browser type
Sys.Browser = {};
Sys.Browser.InternetExplorer = {};
Sys.Browser.Firefox = {};
Sys.Browser.Safari = {};
Sys.Browser.Opera = {};
Sys.Browser.Chrome = {};
Update the if-then logic to search for Chrome
else if (navigator.userAgent.indexOf(' Firefox/') > -1) {
Sys.Browser.agent = Sys.Browser.Firefox;
Sys.Browser.version = parseFloat(navigator.userAgent.match(/ Firefox\/(\d+\.\d+)/)[1]);
Sys.Browser.name = 'Firefox';
Sys.Browser.hasDebuggerStatement = true;
}
else if (navigator.userAgent.indexOf(' Chrome/') > -1) {
Sys.Browser.agent = Sys.Browser.Chrome;
Sys.Browser.version = parseFloat(navigator.userAgent.match(/ Chrome\/(\d+\.\d+)/)[1]);
Sys.Browser.name = 'Chrome';
Sys.Browser.hasDebuggerStatement = true;
}
else if (navigator.userAgent.indexOf(' AppleWebKit/') > -1) {
Sys.Browser.agent = Sys.Browser.Safari;
Sys.Browser.version = parseFloat(navigator.userAgent.match(/ AppleWebKit\/(\d+(\.\d+)?)/)[1]);
Sys.Browser.name = 'Safari';
Be sure to put the Chrome check before Safari. If you need help replacing the Framework script with your custom version, read this.
UPDATE:
I created a test page and put the following controls on it:
<asp:ScriptManager ID="scriptManager1" runat="server" />
<asp:UpdatePanel ID="panel1" runat="server" ChildrenAsTriggers="true">
<ContentTemplate>
<asp:DropDownList ID="ddlTest" runat="server" AutoPostBack="true">
<asp:ListItem Value="0" Text="Item 1" />
<asp:ListItem Value="1" Text="Item 2" />
</asp:DropDownList>
<asp:Literal ID="litTest" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
And wrote the following codebehind:
protected override void OnInit(EventArgs e)
{
ddlTest.SelectedIndexChanged += new EventHandler(ddlTest_SelectedIndexChanged);
base.OnInit(e);
}
void ddlTest_SelectedIndexChanged(object sender, EventArgs e)
{
litTest.Text = "Selected: " + ddlTest.SelectedItem.Text;
}
The Updatepanel works fine in Chrome, with no modification of the Ajax library. So, I think something else is causing this problem. You're going to need to isolate the cause of the problem through a process of elimination. Start with something simple like this example, and work up to what you have a piece at a time.
It is not an appropriate suggestion to use MVC and jQuery instead of WebForms and ASP.NET AJAX. One should understand all the pros and cons of the technologies and approaches to choose from.
First, MVC is a design pattern and has nothing to do with the particular frameworks mentioned. You can easily implement an MVC pattern with WebFroms. There are many different implementations of MVC for ASP.NET and WebForms.
Second, jQuery, being a great JavaScript library, does not allow any integration with and does not leverage server side ASP.NET functionality, as opposed to ASP.NET AJAX framework that comes standard with the ASP.NET 3.5+ and fully utilizes ASP.NET features, such as server side mark-up, ScriptManager control, server-side script combining, localization and globalization, etc.
Third, jQuery can be easily used in conjunction with ASP.NET and ASP.NET AJAX frameworks thus enhancing client-side programming. Microsoft has announced that jQuery will be shipped with the next ASP.NET 4.0 and for now you can just add it to your project manually.
I just ran into a similar problem today (although I wasn't using Ajax), and found a fix. See the third comment down on this blog post.
I have the same problem. I've got a dropdown inside a ajax postback and need to do an update when the selected index changes. It works with a basic page in a new project too.
After adding the Webkit script mentioned in the other answers I still get the same problem and when running the javascript debugger in Chrome I get this error:
uncaught exception ReferenceError: evt is not defined
UPDATE: SOLUTION
I found that in my case it was a CustomValidator that was interfering with the event handler. Setting EnableClientScript to false fixed the issue.
You can check out solution
http://dotnetguts.blogspot.com/2009/05/dropdownlist-autopostback-problem-with.html