JS function calling from the code behind Issue - c#

I have a JS function (Show alert box), and have a link button in ASP page, On click event from code behind for this link button I want to call this function and then redirect to certain page.
ASP Code
<script type="text/javascript" language="javascript">
function myFunction() {
// executes when HTML-Document is loaded and DOM is ready
alert("document is ready!");
}
</script>
<div>
<asp:LinkButton ID="lnkbtnChangePassword" runat="server" Text="Change Passwrod" OnClick="lnkbtnChangePassword_Click" ></asp:LinkButton>
</div>
C# Code
protected void lnkbtnChangePassword_Click(object sender, EventArgs e)
{
ClientScript.RegisterStartupScript(this.GetType(), "CallMyFunction", "myFunction()", true);
Response.Redirect("myPage.aspx");
}
Here when I click on the link button, it simply don't display the alert box/window and redirect to the page.

You should use LinkButton.ClientClick instead of LinkButton.Click event.
Click event is handled on server. When user clicks the button, page is posted back to server and code is executed on server side.
ClientClick event is really a name of JavaScript function which should be executed.
You should probably do something like this:
<asp:LinkButton ID="lnkbtnChangePassword" runat="server" Text="Change Passwrod" OnClientClick="showMyAlertAndSubmit()"></asp:LinkButton>
<script type="text/javascript">
function showMyAlertAndSubmit(){
alert("Your password is being changed");
// submit your form
}
</script>
Why your current code doesn't work
You currently send script for showing a message, and redirect at the same time. This means that browser receives instructions to show a message and to redirect, and it redirects the user before showing the message. One approach could be to redirect from client side. For example:
protected void lnkbtnChangePassword_Click(object sender, EventArgs e)
{
ClientScript.RegisterStartupScript(this.GetType(), "CallMyFunction", "myFunction()", true);
}
and on client side
function myFunction() {
// show your message here
// do other things you need
// and then redirect here. Don't redirect from server side with Response.Redirect
window.location = "http://myserver/myPage.aspx";
}
Other options
Since you need to first perform checks on server side before saving data and redirecting, you can use ajax to call server without performing postback.
Remove Click handler, and only use ClientClick:
function myFunction() {
$.ajax({
type: "POST",
url: "myPage.aspx/MyCheckMethod",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(msg) {
ShowAlert();
window.location = "http://myserver/mypage.aspx";
}
});
}
For more details please check this tutorial.

Change your code like this:
ASP Code
<script type="text/javascript" language="javascript">
function myFunction() {
// executes when HTML-Document is loaded and DOM is ready
alert("document is ready!");
}
</script>
<div>
<asp:LinkButton ID="lnkbtnChangePassword" runat="server" Text="Change Passwrod" OnClick="lnkbtnChangePassword_Click" OnClientClick="myFunction()" ></asp:LinkButton>
</div>
C# Code
protected void lnkbtnChangePassword_Click(object sender, EventArgs e)
{
Response.Redirect("myPage.aspx");
}

Change your javascript function to :
<script type="text/javascript" language="javascript">
function myFunction() {
// alert will stop js execution
alert("document is ready!");
// then reload your page
__doPostBack('pagename','parameter');
}
</script>
And call it from code-behind with this function :
protected void lnkbtnChangePassword_Click(object sender, EventArgs e)
{
//do your job here
//then call your js function
ScriptManager.RegisterStartupScript(this,this.GetType(), "CallMyFunction", "myFunction();", true);
}

What you're missing is waiting for JavaScript alert dialog to popup and then redirect to the page.
In order to do this you need to tell button to wait for JavaScript alert dialog to popup and then do the Server side work after.
ASPX:
<head runat="server">
<title></title>
<script type="text/javascript">
function alertBeforeSubmit() {
return alert('Document Ready');
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button Text="Do" runat="server" ID="btnSubmit" OnClick="btnSubmit_Click" OnClientClick="return alertBeforeSubmit();" />
</div>
</form>
</body>
CS:
protected void btnSubmit_Click(object sender, EventArgs e)
{
Response.Redirect("Default.aspx");
}

Related

How to call a javascript function before and after button click event call in asp.net

i have created "ButtonClick" function in ASP.NET as following:
<asp:Button ID="btnLogin" runat="server" Text="Login" CssClass="button" CausesValidation="true" onclick="btnLogin_Click"/>
i want to know, is it possible to call a javascript function before and after calling asp.net button click function...???
Thanks.
Yes it's possible, here is quick example:
Java script function to call.
<script type="text/javascript">
function clientValidate() {
alert("execute before");
return true;
}
function executeAfter() {
alert("execute after");
}
</script>
Here is snapshoot for button
<asp:Button ID="btnLogin" runat="server" Text="Login" CausesValidation="true" OnClientClick="clientValidate()" onclick="btnLogin_Click"/>
Notice property onClientClick="clientValidate()", it will be trigger script before button click on the server.
On the server side:
protected void btnLogin_Click(object sender, EventArgs e)
{
ScriptManager.RegisterClientScriptBlock(this, GetType(), "none", "<script>executeAfter();</script>", false);
}
Notice executeAfter();, it will trigger javascript execution after server event.
Don't forget to place <asp:ScriptManager runat="server"></asp:ScriptManager> in your aspx file.
Hope it help
put this on your page and make sure you have a scriptmanager. these codes will handle your pre & post postbacks.
var prm, postBackElement;
if (typeof Sys != "undefined") {
prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(InitializeRequest);
prm.add_endRequest(EndRequest);
}
function InitializeRequest(sender, e) {
postBackElement = e.get_postBackElement();
if (postBackElement.id == "btnLogin") {
// before click codes
}
}
function EndRequest(sender, e) {
if (postBackElement.id == "btnLogin") {
// after click codes
}
}
Before:
<script type="text/javascript">
function executeBefore() {
alert("execute before");
}
</script>
<asp:Button ID="btnLogin" runat="server" Text="Login" CausesValidation="true" OnClientClick="executeBefore()" onclick="btnLogin_Click"/>
After:
<script type="text/javascript">
function executeAfter() {
alert("execute after ");
}
</script>
Add this code to your server side event:
Page.ClientScript.RegisterStartupScript(GetType(), "none", "<script>executeAfter();</script>", false);
If you don't have a master page, or are not using ajax, there is no need to add ScriptManager.
You can call Java scrip function before server side click using OnClientClick():
aspx(design)
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript">
function Test() {
alert('client click');
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button Text="btn" runat="server" ID="btn"
OnClick="btn_Click" OnClientClick="Test()" />
</div>
</form>
</body>
</html>
.cs
protected void btn_Click(object sender, EventArgs e)
{
Response.Write("Server Click");
}
First time you can call your javascript function in Button's OnClientClick event passing your function name.
<asp:Button ID="btnLogin" runat="server" Text="Login" CssClass="button" CausesValidation="true" onclick="btnLogin_Click" OnClientClick="return functionNAME();"/>
Second time, in your button click event btnLogin_Click call js as follow
ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "script", "<script type='text/javascript'>functionNA();</script>", false);
For calling it before, you could consider using onload function, like this example:
<body onload="myFunction()">
For calling it afterwards, just link the button to execute JS onClick?
I don't think I quite understand your intentions.

Call server-side method in the onclick method in jQuery

I have one method in backend coding using c#. Now, I want to call it on onClick event of button using jQuery which is in design part.
Please help me to solve the problem.
Check out below code for example.
.aspx Page
$("#SubmitButton").click(function() {
// Call method BindData();
});
.aspx.cs Page
public void BindData()
{
// Code to bind datalist
}
ASPX
<script type="text/javascript">
function myFunction() {
// some stuff
return true; // important
}
</script>
<asp:Button runat="server" ID="SubmitButton"
OnClientClick="return myFunction();"
OnClick="SubmitButton_Click" />
Code-behind
protected void SubmitButton_Click(object sender, EventArgs e)
{
BindData();
}
By specifying OnClientClick you're telling your button that it should first execute the Javascript method. If the method returns false, there is no postback. However, if it returns true, the button's handler in code-behind will also be called.
if i understand right you want something like this
$("#SubmitButton").click(function() {
$.ajax({
type: "POST",
url: "index.aspx/BindData",
contentType: "application/json; charset=utf-8",
data: JSON.stringify({ }),
dataType: "json",
});
});
and make your method static and add attribute WebMethod like:
[WebMethod]
public static void BindData()
{
// Code
}
but you will not be able to change the state of server controls
in your css :
.hide
{
display:none;
}
then
<asp:Button runat="server" id="btn" onclick="btn_OnClick" CssClass="hide"/>
<div onclick="TestCall();return true;">Click Me !!</div>
<script type="text/javascript">
function TestCall()
{
var btn = $('#<%= btn.ClientID %>');
btn.click();
}
</script>
hope , helps you ;)
Add a APSBUTTON set onclick method on code behind then set CssClass to Hide means declare a style class contain display:none like this
<style>
.hide
{
display:none;
}
</style>
Button Sample :
<asp:Button ID="Button1" runat="server" Text="Button" CssClass="hide" OnClick="Button1_Click" />
JavaScript Sample :
<script type="text/javascript">
//With jQuery
$('#<%=Button1.ClientID%>').click();
</script>
that should be work for this case
good luck

No response when call button click in javascript

Good day,
I have a aspx contain a button with ID button1, the following is my aspx code :
<div>
<asp:LinkButton ID="lnkView" CommandName="VIEW" runat="server">View</asp:LinkButton>
<asp:Button ID="button1" runat="server" Text="OK" onclick="button1_Click" />
</div>
/*
some code here
*/
<script>
function test()
{
document.getElementById("<%=button1.ClientID %>").click();
alert("hello");
return true;
}
</script>
The following is my aspx code behind:
//some code here
lnkView.Attributes.Add("onclick", "return test()");
//some code here
protected void button1_Click(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "Javascript", "<script>alert('Record Added Successfully')</script>", false);
}
As you can see, my linkView link button have a javascript function test() when click on it.
I can alert the "Record Added Successfully" by click on the Button1.
However, when I click on linkView link button, the "Record Added Successfully" didnt alert, it only alert "Hello".
I think I am missunderstand in some programming concept.
Kindly advise.
Thanks.
This will trigger the event in code behind.
Try this in your .aspx page:
//Code:
<script type="text/javascript">
function test(parameter)
{
__doPostBack('button1_Click', parameter)
}
</script>
You can fix this by returning false instead of true as the result of the function test(). This way you will cancel default behavior of the link with ID lnkView ie sending form

Disabling backbutton of browser in C#

<script type="text/javascript">
{
function DisableBackButton() {
window.history.forward()
}
DisableBackButton();
window.onload = DisableBackButton;
window.onpageshow = function (evt) { if (evt.persisted) DisableBackButton() }
window.onunload = function () { void (0) }
}
</script>
I am using the following code in the master page to diable the back button.
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetExpires(DateTime.UtcNow.AddHours(-1));
Response.Cache.SetNoStore();
Response.ExpiresAbsolute = DateTime.Now.AddDays(-1d);
Response.Expires = -1500;
Response.CacheControl = "no-cache";
Page.Response.Cache.SetCacheability(HttpCacheability.NoCache);
I have a master page in that logout button is there once user click on that user will be redirected to logout page. This is working fine and once I am clicking on back button it is taking me to the last page I browsed. Even I tried with JavaScript.
I am creating timing out the session after 5 minutes. When session expires user will be redirected to session expiry page there also backbutton is taking me to the last page browsed.
Here this JavaScript functionality will work in all browsers and prevent users navigating back to previous page by hitting on browser back button check below piece of JavaScript code
<script type="text/javascript" language="javascript">
function DisableBackButton() {
window.history.forward()
}
DisableBackButton();
window.onload = DisableBackButton;
window.onpageshow = function(evt) { if (evt.persisted) DisableBackButton() }
window.onunload = function() { void (0) }
</script>
We need to place above script in header section of a page wherever we need to prevent users navigate back to another page by using browser back button.
I will explain our requirement with an example I have two pages Defaul1.aspx and Default2.aspx now I will redirect from Default1.aspx page to Defaul2.aspx page. After come from Defaul1.aspx page to Default2.aspx if I try to navigate back to Default1.aspx page from Defaul2.aspx then I want prevent user navigate back to previous page (Defaul1.aspx). To achieve this functionality place above JavaScript function in header section of required page.
After add our JavaScript functionality to our page that code will be like this
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Disable Browser Back buttons</title>
<script type="text/javascript" language="javascript">
function DisableBackButton() {
window.history.forward()
}
DisableBackButton();
window.onload = DisableBackButton;
window.onpageshow = function(evt) { if (evt.persisted) DisableBackButton() }
window.onunload = function() { void (0) }
</script>
</head>
<body >
<form id="form1" runat="server">
<div>
First Page
</div>
<div>
<asp:Button id="btnFirst" runat="server" Text="Go to First Page" PostBackUrl="~/Default.aspx" />
<asp:Button ID="btnSecond" runat="server" Text="Go to Second Page" PostBackUrl="~/Default2.aspx" />
<asp:Button ID="btnThree" runat="server" Text="Go to Third Page" PostBackUrl="~/Default3.aspx" />
</div>
</form>
</body>
</html>
We can also achieve this by disabling browser caching in code behind write the following lines of code in Page_Init event or Page_Load event and don’t forgot to add namespace using System.Web; because HttpCacheability related to that namespace.
protected void Page_Init(object sender, EventArgs e)
{
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetExpires(DateTime.Now.AddSeconds(-1));
Response.Cache.SetNoStore();
}
We need to place this code in a page wherever we need to disable browser back button
<script type="text/javascript" language="javascript">
window.onload = function () {
noBack();
}
function noBack() {
window.history.forward();
}
</script>
<body onpageshow="if (event.persisted) noBack();">
</body>
Hello,
You can do it like this,
Implement this code in master page
I have implemented this and it worked for me..
<script language="JavaScript">
this.history.forward(-1);
Redirect to Logout.aspx page on clicking "logout"
Add a new page as Logout.aspx with following body content.
Please wait. You are Logging out.
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Timer ID="Timer1" runat="server" Interval="1000" ontick="Timer1_Tick">
</asp:Timer>
add javascript as below
function noBack() {
window.history.forward()
}
noBack();
window.onload = noBack;
window.onpageshow = function (evt) { if (evt.persisted) noBack(); }
window.onunload = function () { void (0); }
Logout.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
Response.Cache.SetExpires(DateTime.UtcNow.AddMinutes(-1));
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetNoStore();
}
protected void Timer1_Tick(object sender, EventArgs e)
{
Response.Redirect("Login.aspx"));
}
Source : http://geekswithblogs.net/Frez/archive/2010/05/18/back-button-issue-after-logout-in-asp.net.aspx
When user clicks logout button, you should write single line to clear the session.
Session.Abondon();
and navigate to logout page or login page. So that once user clicks logout button, he cannot go back becaause his session was cleared.
To disable the back button of the browser write the below code at master page header part as
<script language="JavaScript" type="text/javascript">
window.history.forward();
</script>
<script type="text/javascript">
function DisableBackButton() {
window.history.forward()
}
DisableBackButton();
window.onload = DisableBackButton;
window.onpageshow = function (evt) { if (evt.persisted) DisableBackButton() }
window.onunload = function () { void (0) }
</script>

Prevent Postback after opening jQuery dialog box

Page:
<body>
<form id="frmLogin" runat="server">
<asp:Button ID="btnClick" OnClientClick="openConfirmDialog();" OnClick="PopulateLabel" runat="server"/>
<div id="divDialog"></div>
<asp:Label ID="lblText" runat="server"></asp:Label>
</form>
</body>
JS
<script type="text/javascript">
$(document).ready(function() {
$("#divDialog").dialog({autoOpen: false,
buttons: { "Ok": function()
{
$(this).dialog("close");
},
"Cancel": function()
{
$(this).dialog("close");
}
}
});
});
function openConfirmDialog()
{
$("#divDialog").dialog("open");
}
C#
protected void Page_Load(object sender, EventArgs e)
{
lblText.Text = "";
}
protected void PopulateLabel(object sender, EventArgs e)
{
lblText.Text = "Hello";
}
This code opens me a dialog box with Ok and Cancel button but it do not wait for user activity and post the page immediately and the label gets populated. I need to call the c# function based on user activity. If user clicks "Ok" label should get populated and if user clicks "Cancel" it should not call the c# function. How do I achieve this?
First, to prevent the page from immediately posting back to the server, you need to cancel the default behavior of the click event by returning false from your handler:
<asp:Button ID="btnClick" runat="server" OnClick="PopulateLabel"
OnClientClick="openConfirmDialog(); return false;" />
Next, you need to perform the postback yourself when your Ok button is clicked:
$("#divDialog").dialog({
autoOpen: false,
buttons: {
"Ok": function() {
$(this).dialog("close");
__doPostBack("btnClick", "");
},
"Cancel": function() {
$(this).dialog("close");
}
}
});
Note that the first argument to __doPostBack() is the name of the control (its UniqueID in ASP.NET terminology). Since the button is a direct child of the <form> element, we can hardcode its id in the __doPostBack() call, but things will get more complicated if it resides in a container hierarchy. In that case, you can use ClientScript.GetPostBackEventReference() to generate the appropriate call to __doPostBack().
EDIT: Since your page does not contain any postback-enabled control, __doPostBack() won't be defined on the client side. To work around that problem, you can use a LinkButton control instead of a Button control.
Added another button and used the jQuery click() event to trigger new button's click event which will in turn trigger the respective event handler in C#

Categories

Resources