Menu
<script src="../../Scripts/MicrosoftAjax.debug.js" type="text/javascript"></script>
<script type="text/javascript">
function loginOK()
{
var item = document.getElementById('statusLabel');
item.innerHTML = "OK";
document.getElementById('LoadImg').style.visibility = 'hidden';
}
function process()
{
var lab = document.getElementById('statusLabel');
lab.innerHTML = 'Checking...';
lab.style.color = 'Black';
document.getElementById('LoadImg').style.visibility = 'visible';
}
function fail()
{
var lab = document.getElementById('statusLabel');
lab.innerHTML = 'Login is being used';
lab.style.color = 'Red';
document.getElementById('LoadImg').style.visibility = 'hidden';
}
</script>
<div style="width:30%; float:left;">
<label for="Login">Login:</label>
<%= Html.TextBoxFor(model=>model.Login) %>
<%= Html.ValidationMessageFor(model=>model.Login) %>
<img id="LoadImg" alt="" src="../../Content/Images/ajax-loader.gif" style="visibility:hidden;"/>
<br />
<label id="statusLabel" />
<br />
<%=Ajax.ActionLink("CheckLogin","CheckLoginAvailability", "Account",
new AjaxOptions { UpdateTargetId = "statusLabel", OnBegin = "process", OnFailure = "fail", OnSuccess="loginOK"})%>
</div>
and, in the AccountController:
[AcceptVerbs(HttpVerbs.Post)]
public void CheckLoginAvailability(string login)
{
//do some job
}
And, FireBug says that /Account/CheckLoginAvailability is not found. Also, after callback that ActionLink is hidden. Why ?
559
You are talking about Ajax.BeginForm in your question but this is nowhere to be seen in the markup you provided. There are a couple of issues that I can see with your code:
ActionResult. Yeah I know, you will say that this is possible, right, but that's against any good practices, conventions and rendering your controllers unit-test friendly.document.getElementById, innerHTML, style.color, style.visibility, etc... which is not guaranteed to work cross browser.Here's what I would suggest you to improve this. While this doesn't answer your question, take it as an alternative approach.
As always the first thing to deal with is to define a model which in your case might look something like this:
public class LoginViewModel
{
public string Login { get; set; }
}
Of course you might wish to add other fields such as Password, but this is out of scope for the moment. The next step is to write a controller dealing with this model (in parallel you should be already setting a unit-test for the future controller to prepare the ground):
public class HomeController : Controller
{
public ActionResult Index()
{
// Simply return the Login form
return View(new LoginViewModel());
}
[HttpPost]
public ActionResult Index(LoginViewModel model)
{
// Deal with the actual authentication, etc...
throw new NotImplementedException();
}
[HttpPost]
public ActionResult CheckLoginAvailability(LoginViewModel model)
{
// TODO: query your datasource to determine whether
// model.Login is taken
// For this purpose we will suppose that it is taken
bool isLoginTaken = true;
// return a JSON object containing the result
return Json(new { IsLoginTaken = isLoginTaken });
}
}
The last part is to paint the screen:
<%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage<SomeNs.Models.LoginViewModel>" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Login</title>
<!-- Use a separate CSS to avoid mixing markup with styling -->
<link rel="stylesheet" type="text/css" href="<%: Url.Content("~/content/site.css") %>" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
<!-- Always use HTML helpers when dealing with Urls -->
<script type="text/javascript" src="<%: Url.Content("~/scripts/login.js") %>"></script>
</head>
<body>
<% using (Html.BeginForm()) { %>
<%: Html.LabelFor(x => x.Login) %>:
<%: Html.TextBoxFor(x => x.Login) %>
<%: Html.ValidationMessageFor(x => x.Login) %>
<br/>
<!-- Always use HTML helpers when dealing with Urls -->
<img id="loadImg" alt="" src="<%: Url.Content("~/content/images/ajax-loader.gif") %>" style="display:none;" />
<br />
<div id="statusLabel"></div>
<br />
<!-- Give this link an id so that we can easily identify it from javascript -->
<%: Html.ActionLink("CheckLogin", "CheckLoginAvailability", "Home", null, new { id = "checkLogin" })%>
<input type="submit" value="Login" />
<% } %>
</body>
</html>
And the last part is to unobtrusively attach our javascript (using jQuery of course) in the login.js file:
// When the DOM is ready
$(function () {
// Attach a click handler to the checkLogin link
$('a#checkLogin').click(function () {
// When this link is clicked send an AJAX POST request
// to the address this link is pointing to
$.ajax({
type: 'POST',
url: this.href,
// Pass as parameter in the POST body the login
// entered by the user
data: { login: $('#Login').val() },
beforeSend: function () {
// show the spinner image before sending any AJAX request
// to inform the user of an ongoing activity
$('#loadImg').show();
},
complete: function () {
// hide the spinner image when the AJAX request completes
// no matter if it succeeded or not
$('#loadImg').hide();
},
success: function (result) {
// if the AJAX request succeeds
// query the IsLoginTaken property
// of the resulting JSON object
if (result.IsLoginTaken) {
// Show the status label with red if the login is taken
$('#statusLabel').html('Login is being used').css('color', 'red');
} else {
// Show the status label in black if the login is not taken
$('#statusLabel').html('OK').css('color', 'black');
}
}
});
return false;
});
});
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