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
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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 the following code in my aspx file:
<button type="button" id="btnAskQuestion" runat="server" onserverclick="btnAskQuestion_Click">Ask Question</button>
I've tried every combination of onclick="return false;" and onclick="preventDefault()" I can think of, including putting them in the javascript function that gets called. Everything I try has one of two results: either I get a postback, or the server side code (btnAskQuestion_Click) never executes.
Any idea what I might be doing wrong?
You cannot execute server-side code this way, using onserverclick causes postback.
If you wish to prevent full page refresh and still execute server-side code, you have to call a client-side JS function via onclick and execute an AJAX call from there.
Another alternative is to use your button as a trigger for UpdatePanel - this way only partial postback will be performed.
Try using the property UseSubmitBehavior="false" in the button markup.
or you can use a "trick" :
Markup
<button onclick="myFunction()">Click Me!</button>
<div style="display:none">
<asp:Button runat="server" id="btnButton" .../>
</div>
js
function myFunction()
{
if (true statement)
$("[id$=btnButton]").click();
else
alert("false");
}
What this does is that you handle stuff with normal markup and do the logic using js. And you can trigger a click of the button that do something in the server.
There're OnClick, that fires on server and OnClientClick that fires on client browser. You should do this:
<asp:Button ID="btnAskQuestion" runat="server"
OnClick="btnAskQuestion_Click"
OnClientClick="return myfunction();">Ask Question</asp:button>
If myFunction returns true, then you will have a postback to the server.
My answer is appropriate only for ASP:Button, not the button control you are working with. Given the choice, I'd switch to ASP:Button.
You're looking for OnClientClick. If you put your JavaScript code there, it will kill the PostBack before it can hit the server.
On the other hand, if you're looking to execute server code without a PostBack, that's impossible. The PostBack is what triggers the server to act.
I have several text boxes on a page. I want to save the text in the corresponding TextBox on LostFocus. It is to ensure the data is not lost when power failure or internet connectivity is lost. How can I accomplish something like this?
Another solution would be to use an UpdatePanel. You could then leverage server-side events rather than an event handler. You're markup might look something like this:
<asp:ScriptManager ID="ScriptManager" runat="server" />
<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server">
<asp:TextBox ID="SomeTextBox" runat="server" TextChanged="SomeTextBox_TextChanged" AutoPostBack="true" />
</asp:UpdatePanel>
</asp:ScriptManager
and then in the TextChanged handler you could do your work.
Explanation: the TextChanged event will fire on the text box in which the text was actually changed when the post back occurs. The AutoPostBack property is necessary so that the page will in fact post back when the text box loses focus.
One final thing to remember, you will probably need to leverage this.IsPostBack on the page in the Load handler because every time a control is updated it's going to reconstruct the page. It's common that logic in the Load handler only needs to execute one time, but that would pose a problem if you didn't check to see if it was a post back because then it would execute every single time you left a text box.
Use jquery.
First on attach blur event handler, where you call ajax method to server passing new value of the textbox.
Handle this ajax event on serverside and write your data to the database or anywhere else.
Here is a piece of code that may help.
$('#textbox_id').blur(function() {
$.ajax({url:"handler_url.ashx?textbox_value=" + $('#textbox_id').val()});
});
Then create your ashx handler on server and handle your requests with ProcessRequest method. From there you will have access to Request.QueryString where new value of textbox will be stored.
I was wondering if it was possible to validate the ajax toolkit combobox with a regular expression validator. I allow the user to enter values, but only want certain values ( regex [0-9]{0,1}[0-9]{1}|-7|-8|-9) to be allowed. I could use the custom validator, but I would need to also create javascript function to validate on the client side. If there is a better way I would love to hear it. Thanks. Here is the combobox code:
<asp:ComboBox CssClass="required" DropDownStyle="Simple"
ID="DaysDeployed" Width="50" runat="server">
<asp:ListItem Selected="True" Text="" Value="" />
<asp:ListItem Text="Refused" Value="-7" />
<asp:ListItem Text="Don't Know" Value="-8" />
<asp:ListItem Text="Missing Data" Value="-9" />
</asp:ComboBox>
Summary: Instead of using an asp.net button that would normally trigger your postback, make one using html. Have the html button run a javascript function that first checks the regex validation, then (if valid) runs the postback function.
First, I would remove the asp.net button that you use to trigger the server-side code, and replace it with a client-side button. You can follow the steps in another answer of mine if you need help creating this button. Here is the link:
https://stackoverflow.com/questions/14062993/input-type-image-onclick-will-trigger-its-event-but-not-act-well-on-funct/14063911#14063911-Stack Overflow
Second, the javascript function should first validate the data using a regex function. Use something like this:
function validateCombobox(myComboboxValue) {
if(myComboboxValue.match(regularExpressionString)===null){
return false
} else {
return true
};
};
***Note: Regex is a weak area for me so you may need to revise this script a little.
Third, if the input is validated using the script above, then call the postback using javascript. To do this, follow these steps:
Create an on the asp page. This is necessary
because without it, the site will not generate event handlers for
the needed buttonclick event.
Set the link-button's css display property to 'none'. Beware that
link-button's "Visible" attribute my be set to true (this is because
asp.net does not even render the code for controls with a false
visible attribute). To illustrate, if your link-button's cssClass
name is myButton, add this to your css file:
.myButton
{
display: none;
}
Now that the button is created and properly hidden, you can add the
postback function to your javascript function. The postback function
has two parameters, the first is the client side ID of the
link-button control that we created. Beware that the client-side
IDs of asp.net controls are not the same as the ID you assign it
during development. Because of this, we use <%=Control.ClientId %>
to get the control's client ID. If your link-button ID is
"myLinkButton", the following should be your postback function:
__doPostBack('<%=myLinkButton.clientid %>','')
Please note that there are two underscore characters in the
beginning of this function.
Here is an example of the regex validation function and the javascript function that should be called by your new button:
function validateCombobox(myComboboxValue) {
if(myComboboxValue.match(regularExpressionString)===null){
return false
} else {
return true
};
};
function comboBoxButton_click(){
var myComboboxValue = $('#<%=myComboBox.clientid %>').val();
if(validateCombobox(myComboboxValue)==true){
__doPostBack('<%=myLinkButton.clientid %>','');
};
};
I have a lot of distractions at the moment and am a little scatter-brained, so forgive me if these instructions are a little confusing. If you need more assistance, feel free to comment and I'll check back soon.
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 :)