Disable the postback on an <ASP:LinkButton> - asp.net

I have an ASP.NET linkbutton control on my form. I would like to use it for javascript on the client side and prevent it from posting back to the server. (I'd like to use the linkbutton control so I can skin it and disable it in some cases, so a straight up tag is not preferred).
How do I prevent it from posting back to the server?

ASPX code:
<asp:LinkButton ID="someID" runat="server" Text="clicky"></asp:LinkButton>
Code behind:
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
someID.Attributes.Add("onClick", "return false;");
}
}
What renders as HTML is:
<a onclick="return false;" id="someID" href="javascript:__doPostBack('someID','')">clicky</a>
In this case, what happens is the onclick functionality becomes your validator. If it is false, the "href" link is not executed; however, if it is true the href will get executed. This eliminates your post back.

This may sound like an unhelpful answer ... But why are you using a LinkButton for something purely client-side? Use a standard HTML anchor tag and set its onclick action to your Javascript.
If you need the server to generate the text of that link, then use an asp:Label as the content between the anchor's start and end tags.
If you need to dynamically change the script behavior based on server-side code, consider asp:Literal as a technique.
But unless you're doing server-side activity from the Click event of the LinkButton, there just doesn't seem to be much point to using it here.

You can do it too
...LinkButton ID="BtnForgotPassword" runat="server" OnClientClick="ChangeText('1');return false"...
And it stop the link button postback

Just set href="#"
<asp:LinkButton ID="myLink" runat="server" href="#">Click Me</asp:LinkButton>

I think you should investigate using a HyperLink control. It's a server-side control (so you can manipulate visibility and such from code), but it omits a regular ol' anchor tag and doesn't cause a postback.

Just been through this, the correct way to do it is to use:
OnClientClick
return false
as in the following example line of code:
<asp:LinkButton ID="lbtnNext" runat="server" OnClientClick="findAllOccurences(); return false;" />

In C#, you'd do something like this:
MyButton.Attributes.Add("onclick", "put your javascript here including... return false;");

Instead of implement the attribute:
public partial class _Default : System.Web.UI.Page{
protected void Page_Load(object sender, EventArgs e)
{
someID.Attributes.Add("onClick", "return false;");
}}
Use:
OnClientClick="return false;"
inside of asp:LinkButton tag

To avoid refresh of page, if the return false is not working with asp:LinkButton use
href="javascript: void;"
or
href="#"
along with OnClientClick="return false;"
<asp:LinkButton ID="linkPrint" runat="server" CausesValidation="False" href="javascript: void;"
OnClientClick="javascript:self.print();return false;">Print</asp:LinkButton>
Above is code will call the browser print without refresh the page.

call java script function on onclick event.

Have you tried to use the OnClientClick?
var myLinkButton = new LinkButton { Text = "Click Here", OnClientClick = "JavaScript: return false;" };
<asp:LinkButton ID="someID" runat="server" Text="clicky" OnClientClick="JavaScript: return false;"></asp:LinkButton>

Something else you can do, if you want to preserve your scroll position is this:
<asp:LinkButton runat="server" id="someId" href="javascript: void;" Text="Click Me" />

Why not use an empty ajax update panel and wire the linkbutton's click event to it? This way only the update panel will get updated, thus avoiding a postback and allowing you to run your javascript

No one seems to be doing it like this:
createEventLinkButton.Attributes.Add("onClick", " if (this.innerHTML == 'Please Wait') { return false; } else { this.innerHTML='Please Wait'; }");
This seems to be the only way that works.

In the jquery ready function you can do something like below -
var hrefcode = $('a[id*=linkbutton]').attr('href').split(':');
var onclickcode = "javascript: if`(Condition()) {" + hrefcode[1] + ";}";
$('a[id*=linkbutton]').attr('href', onclickcode);

You might also want to have the client-side function return false.
<asp:LinkButton runat="server" id="button" Text="Click Me" OnClick="myfunction();return false;" AutoPostBack="false" />
You might also consider:
<span runat="server" id="clickableSpan" onclick="myfunction();" class="clickable">Click Me</span>
I use the clickable class to set things like pointer, color, etc. so that its appearance is similar to an anchor tag, but I don't have to worry about it getting posted back or having to do the href="javascript:void(0);" trick.

use html link instead of asp link and you can use label in between html link for server side
control

Related

how to open a page in new tab on button click in asp.net?

I want to open a page in new tab of browser on button click.
I have searched a lot on google but i couldn't find anything.
Here is my button.
<asp:Button ID="btnNewEntry" runat="Server" CssClass="button" Text="New Entry" OnClick="btnNewEntry_Click" />
protected void btnNewEntry_Click(object sender, EventArgs e)
{
Response.Redirect("New.aspx");
}
Can you please help me how i can do this ?
You could use window.open. Like this:
protected void btnNewEntry_Click(object sender, EventArgs e)
{
Page.ClientScript.RegisterStartupScript(
this.GetType(),"OpenWindow","window.open('YourURL','_newtab');",true);
}
Why not just call window.open straight from OnClick?
<asp:Button ID="btnNewEntry" runat="Server" CssClass="button" Text="New Entry" OnClick="window.open('New.aspx')" />
Try This
Link
Take care to reset target, otherwise all other calls like Response.Redirect will open in a new tab, which might be not what you want.
<asp:LinkButton OnClientClick="openInNewTab();" .../>
In javaScript:
<script type="text/javascript">
function openInNewTab() {
window.document.forms[0].target = '_blank';
setTimeout(function () { window.document.forms[0].target = ''; }, 0);
}
</script>
Use JavaScript for the main form / Button click event. An example is:
Context.Response.Write("<script language='javascript'>window.open('AccountsStmt.aspx?showledger=" & sledgerGrp & "','_newtab');</script>")
try this rather than redirect...
Response.Write("<script>");
Response.Write("window.open('ClickPicture.aspx','_blank')");
Response.Write("</script>");
Just had the same problem. Client-side wasn't appropriate because the button was posting back information from a listview.
Saw same solution as Amaranth's on way2coding but this didn't work for me.
However, in the comments, someone posted a similar solution that does work
OnClientClick="document.getElementById('form1').target ='_blank';"
where form1 is the id of your asp.net form.
You have to use Javascript since code behind is server side only. I am pretty sure that this works.
<asp:Button ID="btnNewEntry" runat="Server" CssClass="button" Text="New Entry" OnClick="btnNewEntry_Click" OnClientClick="aspnetForm.target ='_blank';"/>
protected void btnNewEntry_Click(object sender, EventArgs e)
{
Response.Redirect("New.aspx");
}
Add this Script
<script type = "text/javascript">
function SetTarget() {
document.forms[0].target = "_blank";
}
</script>
and
<asp:Button ID="BTNpRINT" runat="server" Text="PRINT" CssClass="btn btn-primary" OnClick="BTNpRINT_Click" OnClientClick = "SetTarget();"/>
and
protected void BTNpRINT_Click(object sender, EventArgs e)
{
Response.Redirect(string.Format("~/Print.aspx?ID={0}",txtInv.Text));
}
You can add to your button OnClientClick like so:
<asp:Button ID="" runat="Server" Text="" OnClick="btnNewEntry_Click" OnClientClick="target ='_blank';"/>
This will change the current form's target for all buttons to open in new tab. So to complete the fix you can then use 2 approaches:
For any other button in this form, add to client click a "reset form target" function like so:
function ResetTarget() {
window.document.forms[0].target = '';
}
Add the same code inside the function inside a setTimeout() so the code will reset the form's target after few moments. See this answer https://stackoverflow.com/a/40682253/8445364
Per Open a URL in a new tab (and not a new window) using JavaScript
Nothing an author can do can choose to open in a new tab instead of a new window.
The browser decides between opening a new tab or opening a new window. You cannot control this as a developer.
In vb.net either on button click or on link button click, this will work.
System.Web.UI.ScriptManager.RegisterClientScriptBlock(Me, Me.GetType(), "openModal", "window.open('CertificatePrintViewAll.aspx' ,'_blank');", True)
add target='_blank' after check validation :
<asp:button id="_ButPrint" ValidationGroup="print" OnClientClick="if (Page_ClientValidate()){$('form').attr('target','_blank');}" runat="server" onclick="ButPrint_Click" Text="print" />
You could do this on the ASPX HTML front end to make the button go to a new tab to show page in your ASP.NET site dynamically:
<asp:Button ID="btnNewEntry" CssClass="button" OnClientClick="window.open('https://website','_blank'); return false;" text="WebsiteName" runat="server" />
If the url is dynamic and you want to control it in the code behind
<asp:Button ID="btnNewEntry" runat="Server" Text="New Entry" />
//code behind
var id = 0;
btnNewEntry.OnClientClick = $"window.open('New.aspx?ID={id}')";
A simple solution:
<a href="https://www.google.com" target="_blank">
<button type="button">Open new tab</button>
</a>
You shuld do it by client side. you can place a html hyperlink with target="_blank" and style="display:none".
after that create a javascript function like following
function openwindow(){
$("#hyperlinkid").click();
return false;
}
use this function as onclientclick event handler of the button like onclientclick="return openwindow()"
You need to include a jquery in the page.
Add_ supplier is name of the form
private void add_supplier_Load(object sender, EventArgs e)
{
add_supplier childform = new add_supplier();
childform.MdiParent = this;
childform.Show();
}

how to use image button to open the url in another window

Hi I know how to acheive this in hyperlink by setting target = _blank , how can i do this using image button control , below is my code:
<asp:ImageButton OnClick="test_Click" ImageUrl="/images/contactUs/directionbtn.png" ID="test" runat="server" ValidationGroup="group2" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server"
ControlToValidate="txtPostcode1" ErrorMessage="Postcode is required" ValidationGroup="group2"></asp:RequiredFieldValidator>
<br />
Code behind:
protected void test_Click(object sender, ImageClickEventArgs e)
{
Response.Redirect(String.Format("http://maps.google.co.uk/maps?saddr={0}&daddr=&daddr=Wigan+WN6+0HS,+United+Kingdom&iwloc=1&dq=Tangent+Design", txtPostcode1.Text));
}
Any help or advice will be highly appreciated
protected void Page_Load() {
ControlID.Attributes.Add("target", "_blank");
}
If that doesn't work, try adding this to your ImageButton:
<asp:ImageButton runat="server" OnClientClick="window.open('http://url/to/open');" ></asp:ImageButton>
I just figure it out..
On Page_Load event, put
this.Form.Target = "_blank"; // Will set all link's target to a new window
Then for example in a image button Click event, you put:
Response.Redirect("http://stackoverflow.com");
It will simply open this page in a new tab. Try it :)
you could use the Attributes collection to add "target","_blank"
this should add the target attribute to the anchor link surrounding the image
Add target="_blank" to onClientClick will do the trick
In the code behind.
imgbtn.OnClientClick = "target='blank'";
And you're done.
Try this:
<asp:ImageButton OnClick="test_Click" ImageUrl="/images/contactUs/directionbtn.png" ID="test" runat="server" ValidationGroup="group2" OnClientClick="form1.target ='_blank';" />
this.Form.Target = "_blank";
This way the client can see what he wants in a new page, since the server and what is available and his account in the site available at the beginning PageLoad

Can I create an ASP.NET ImageButton that doesn't postback?

I'm trying to use the ImageButton control for client-side script execution only. I can specify the client-side script to execute using the OnClientClick property, but how do I stop it from trying to post every time the user clicks it? There is no reason to post when this button is clicked. I've set CausesValidation to False, but this doesn't stop it from posting.
I know this problem has already been answered but a simple solution is to return false from the HTML onclick method (i.e. the ASPX OnClientClick method) e.g.
<asp:ImageButton ID="ImageNewLink" runat="server"
ImageUrl="~/images/Link.gif" OnClientClick="DoYourStuff(); return false;" />
Returning false stops the browser from making the request back to the server i.s. stops the .NET postback.
Here's one way you could do it without conflicting with the postback functioning of other controls:
Define your button something like this:
<asp:Button runat="server" Text="Button" UseSubmitBehavior="false" OnClientClick="alert('my client script here');my" />
The "my" ending in the handler for OnClientClick is a way to alias asp.net's __doPostBack client event that forces the postback; we simply override the behavior by doing nothing similar to this script:
<script type="text/javascript">
function my__doPostBack(eventTarget, eventArgument) {
//Just swallow the click without postback of the form
}
</script>
Edit: Yeesh, I feel like I need to take a shower after some of the dirty tricks that I need to pull in order to get asp.net to do what I want.
Another solution would be to define a PostBackUrl that does nothing
<asp:imagebutton runat="server" PostBackUrl="javascript:void(0);" .../>
<image src="..." onclick="DoYourThing();" />
Use a server side Image control
<asp:Image runat="server" .../>
Pretty sure you can add the client onclick event to that.
Solution 1
<asp:ImageButton ID="btn" runat="server" ImageUrl="~/images/yourimage.jpg"
OnClientClick="return false;" />
OR
Solution 2
<asp:ImageButton ID="btn" runat="server" ImageUrl="~/images/yourimage.jpg"
OnClientClick="yourmethod(); return false;" />
In addition (solution 2), your javascript method may be in this form
<script type="text/javascript">
function yourmethod() {
__doPostBack (__EVENTTARGET,__EVENTARGUMENT); //for example __doPostBack ('idValue',3);
}
</script>
in code behind
protected void Page_Load(object sender, System.EventArgs e)
{
if (this.IsPostBack) {
string eventTarget = this.Request("__EVENTTARGET") == null ? string.Empty : this.Request("__EVENTTARGET");
string eventArgument = this.Request("__EVENTARGUMENT") == null ? string.Empty : this.Request("__EVENTARGUMENT");
}
}
This works Great for me:
Use OnClientClick to write your script and PostBackUrl="javascript:void(0);" to avoid postback.
<div class="close_but">
<asp:ImageButton ID="imgbtnEChartZoomClose" runat="server" ImageUrl="images/close.png" OnClientClick="javascript:zoomclosepopup();" PostBackUrl="javascript:void(0);" />
</div>
Use OnClientClick to write your script and PostBackUrl="javascript:void(0);" to avoid postback

How can I assign a callback function to an asp:HyperlinkField?

I want people to click on a link (generated from an asp:HyperlinkField) and have it call a method on the server rather than redirect the user somewhere. Anyone know how to do this?
Thanks,
Matt
I'd use an asp:CommandField or asp:ButtonField instead and use ButtonType=Link - that will look the same as your linkfield, and then you can handle the OnRowCommand event in your grid to run your code.
Use an asp:LinkButton instead. Unless there's a particular reason you're attached to the asp:Hyperlink?
HyperLinkField is used for generating simple hyperlinks in databound controls. Instead you can use ButtonField. Or you can define your own link with TemplateField.
Here is a sample of generating link column which has a server side event :
<asp:templatefield headertext="Link Column">
<itemtemplate>
<asp:LinkButton ID="myLink"
CommandName="MyLinkCommand"
CommandArgument='<%#Bind("TableID") %>'
runat="server">My Link</asp:LinkButton>
</itemtemplate>
</asp:templatefield>
At code behind :
protected void YouGridView_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "MyLinkCommand")
{
// Do stuff
}
}
Why not use a ButtonField instead and set the ButtonType property to a Link? It will look just like a hyperlink.

OnClick vs OnClientClick for an asp:CheckBox?

Does anyone know why a client-side javascript handler for asp:CheckBox needs to be an OnClick="" attribute rather than an OnClientClick="" attribute, as for asp:Button?
For example, this works:
<asp:CheckBox runat="server" OnClick="alert(this.checked);" />
and this doesn't (no error):
<asp:CheckBox runat="server" OnClientClick="alert(this.checked);" />
but this works:
<asp:Button runat="server" OnClientClick="alert('Hi');" />
and this doesn't (compile time error):
<asp:Button runat="server" OnClick="alert('hi');" />
(I know what Button.OnClick is for; I'm wondering why CheckBox doesn't work the same way...)
That is very weird. I checked the CheckBox documentation page which reads
<asp:CheckBox id="CheckBox1"
AutoPostBack="True|False"
Text="Label"
TextAlign="Right|Left"
Checked="True|False"
OnCheckedChanged="OnCheckedChangedMethod"
runat="server"/>
As you can see, there is no OnClick or OnClientClick attributes defined.
Keeping this in mind, I think this is what is happening.
When you do this,
<asp:CheckBox runat="server" OnClick="alert(this.checked);" />
ASP.NET doesn't modify the OnClick attribute and renders it as is on the browser. It would be rendered as:
<input type="checkbox" OnClick="alert(this.checked);" />
Obviously, a browser can understand 'OnClick' and puts an alert.
And in this scenario
<asp:CheckBox runat="server" OnClientClick="alert(this.checked);" />
Again, ASP.NET won't change the OnClientClick attribute and will render it as
<input type="checkbox" OnClientClick="alert(this.checked);" />
As browser won't understand OnClientClick nothing will happen. It also won't raise any error as it is just another attribute.
You can confirm above by looking at the rendered HTML.
And yes, this is not intuitive at all.
Because they are two different kinds of controls...
You see, your web browser doesn't know about server side programming. it only knows about it's own DOM and the event models that it uses... And for click events of objects rendered to it. You should examine the final markup that is actually sent to the browser from ASP.Net to see the differences your self.
<asp:CheckBox runat="server" OnClick="alert(this.checked);" />
renders to
<input type="check" OnClick="alert(this.checked);" />
and
<asp:CheckBox runat="server" OnClientClick="alert(this.checked);" />
renders to
<input type="check" OnClientClick="alert(this.checked);" />
Now, as near as i can recall, there are no browsers anywhere that support the "OnClientClick" event in their DOM...
When in doubt, always view the source of the output as it is sent to the browser... there's a whole world of debug information that you can see.
You are right this is inconsistent. What is happening is that CheckBox doesn't HAVE an server-side OnClick event, so your markup gets rendered to the browser. http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.checkbox_events.aspx
Whereas Button does have a OnClick - so ASP.NET expects a reference to an event in your OnClick markup.
For those of you who got here looking for the server-side OnClick handler it is OnCheckedChanged
I was cleaning up warnings and messages and see that VS does warn about it:
Validation (ASP.Net): Attribute 'OnClick' is not a valid attribute of element 'CheckBox'. Use the html input control to specify a client side handler and then you won't get the extra span tag and the two elements.
Asp.net CheckBox is not support method OnClientClick.
If you want to add some javascript event to asp:CheckBox you have to add related attributes on "Pre_Render" or on "Page_Load" events in server code:
C#:
private void Page_Load(object sender, EventArgs e)
{
SomeCheckBoxId.Attributes["onclick"] = "MyJavaScriptMethod(this);";
}
Note: Ensure you don't set AutoEventWireup="false" in page header.
VB:
Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
SomeCheckBoxId.Attributes("onclick") = "MyJavaScriptMethod(this);"
End Sub
You can do the tag like this:
<asp:CheckBox runat="server" ID="ckRouteNow" Text="Send Now" OnClick="checkchanged(this)" />
The .checked property in the called JavaScript will be correct...the current state of the checkbox:
function checkchanged(obj) {
alert(obj.checked)
}
You can assign function to all checkboxes then ask for confirmation inside of it. If they choose yes, checkbox is allowed to be changed if no it remains unchanged.
In my case I am also using ASP .Net checkbox inside a repeater (or grid) with Autopostback="True" attribute, so on server side I need to compare the value submitted vs what's currently in db in order to know what confirmation value they chose and update db only if it was "yes".
$(document).ready(function () {
$('input[type=checkbox]').click(function(){
var areYouSure = confirm('Are you sure you want make this change?');
if (areYouSure) {
$(this).prop('checked', this.checked);
} else {
$(this).prop('checked', !this.checked);
}
});
});
<asp:CheckBox ID="chk" AutoPostBack="true" onCheckedChanged="chk_SelectedIndexChanged" runat="server" Checked='<%#Eval("FinancialAid") %>' />
protected void chk_SelectedIndexChanged(Object sender, EventArgs e)
{
using (myDataContext db = new myDataDataContext())
{
CheckBox chk = (CheckBox)sender;
RepeaterItem row = (RepeaterItem) chk.NamingContainer;
var studentID = ((Label) row.FindControl("lblID")).Text;
var z = (from b in db.StudentApplicants
where b.StudentID == studentID
select b).FirstOrDefault();
if(chk != null && chk.Checked != z.FinancialAid){
z.FinancialAid = chk.Checked;
z.ModifiedDate = DateTime.Now;
db.SubmitChanges();
BindGrid();
}
gvData.DataBind();
}
}
One solution is with JQuery:
$(document).ready(
function () {
$('#mycheckboxId').click(function () {
// here the action or function to call
});
}
);

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