Leveraging SignalR in conjunction with jQuery to dynamically alter the CSS style of a span

Question

Leveraging SignalR in conjunction with jQuery to dynamically alter the CSS style of a span

Utilizing SignalR to dynamically update a span's color based on real-time data source. The connection is established successfully, but encountering difficulties with updating the css classes on the span.

The issue arises when attempting to update multiple classes on a single element, as the class names are simply appended rather than replaced. Below is the markup:

<span id="activity-@UnitId" class="badge sl-badge-normal connection-false">
    <i id="asxConnected-@UnitId" class="fa fa-rss"></i>
    <span id="activityMessage-@UnitId">
        @Model.ActivityMessage    
    </span>
</span>

Within the outer span, the classes sl-badge-normal and connection-false require modification. sl-badge-normal can be one of the following values:

sl-badge-ok
sl-badge-warning
sl-badge-error
sl-badge-normal

While connection-false can only toggle between that and connection-true.

Note that separate jQuery updates must be performed for these two distinct message types :) The jQuery code for the connection part is as follows:

messageHub.client.notifyAlive = function (aliveMessage, unitId) {
    if (aliveMessage) {
        $('#activity-' + unitId).addClass("connection-true");
    } else {
        $('#activity-' + unitId).addClass("connection-false");
    }
};

And for the badge section, the jQuery code looks like this:

messageHub.client.notifyActivityStatus = function(statusColor, statusText, unitId) {
    $('#activity-' + unitId).addClass("badge " + statusColor);
    $('#activityMessage-' + unitId).text(statusText);
};

The problem lies in the fact that the span will transition from this initial state:

<span id="activity-@UnitId" class="badge sl-badge-normal connection-false">

To this unwanted state:

<span id="activity-@UnitId" class="badge sl-badge-normal connection-false sl-badge-error connection-true">

If anyone could provide a solution or suggest an alternative approach, it would be greatly appreciated. Is it necessary to restate the entire class string each time there's an update, or is there a way to simply swap out individual class names?

jquery html css razor signalr

Answer 1

Answer №1

It seems like you have quite a mix of technologies at play here. Have you thought about incorporating something like knockout.js?

Let me demonstrate with a brief example:

<!DOCTYPE html>
<html>
<head>
 <style>
  .badge { border-width: 3px; }

  .sl-badge-normal { border-color: black; }
  .sl-badge-ok { border-color: green; }
  .sl-badge-warning { border-color: yellow; }
  .sl-badge-error { border-color: red; }

  .connection-true { border-style: solid; }
  .connection-false { border-style: dashed; }
 </style>
</head>
<body>
 <span class="badge" data-bind="css: badgeClass">
  <i class="fa fa-rss"></i>
  <span data-bind="text: activityMessage"></span>
 </span>

 <button data-bind="click: toggleConnection">connection</button>
 <button data-bind="click: toggleStatus">status</button>

 <script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
 <script src="http://cdnjs.cloudflare.com/ajax/libs/knockout/3.0.0/knockout-min.js"></script>

 <script>
  var ViewModel = function(){
    var self = this;
    self.connected = ko.observable(true);
    self.status = ko.observable(0);
    self.activityMessage = ko.observable('activity message');

    self.onlineClass = ko.computed(function(){
      return self.connected() ? 'connection-true' : 'connection-false';
    });

    self.statusClass = ko.computed(function(){
      var statusClasses = ['sl-badge-normal','sl-badge-ok','sl-badge-warning','sl-badge-error'];

      return statusClasses[self.status()];
    });

    self.badgeClass = ko.computed(function(){
      return self.onlineClass() + ' ' + self.statusClass();
    });

    // testing functionality     

    self.toggleConnection = function(){
      self.connected(!self.connected());
    };

    self.toggleStatus = function(){
      self.status((self.status() + 1) % 4);
    };
 };

 $(function(){
  ko.applyBindings(new ViewModel());
 });
</script>

</body>
</html>

Answer 2

It seems like you have quite a mix of technologies at play here. Have you thought about incorporating something like knockout.js?

Let me demonstrate with a brief example:

<!DOCTYPE html>
<html>
<head>
 <style>
  .badge { border-width: 3px; }

  .sl-badge-normal { border-color: black; }
  .sl-badge-ok { border-color: green; }
  .sl-badge-warning { border-color: yellow; }
  .sl-badge-error { border-color: red; }

  .connection-true { border-style: solid; }
  .connection-false { border-style: dashed; }
 </style>
</head>
<body>
 <span class="badge" data-bind="css: badgeClass">
  <i class="fa fa-rss"></i>
  <span data-bind="text: activityMessage"></span>
 </span>

 <button data-bind="click: toggleConnection">connection</button>
 <button data-bind="click: toggleStatus">status</button>

 <script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
 <script src="http://cdnjs.cloudflare.com/ajax/libs/knockout/3.0.0/knockout-min.js"></script>

 <script>
  var ViewModel = function(){
    var self = this;
    self.connected = ko.observable(true);
    self.status = ko.observable(0);
    self.activityMessage = ko.observable('activity message');

    self.onlineClass = ko.computed(function(){
      return self.connected() ? 'connection-true' : 'connection-false';
    });

    self.statusClass = ko.computed(function(){
      var statusClasses = ['sl-badge-normal','sl-badge-ok','sl-badge-warning','sl-badge-error'];

      return statusClasses[self.status()];
    });

    self.badgeClass = ko.computed(function(){
      return self.onlineClass() + ' ' + self.statusClass();
    });

    // testing functionality     

    self.toggleConnection = function(){
      self.connected(!self.connected());
    };

    self.toggleStatus = function(){
      self.status((self.status() + 1) % 4);
    };
 };

 $(function(){
  ko.applyBindings(new ViewModel());
 });
</script>

</body>
</html>

Answer 3

Answer №2

toggleClass can be utilized to switch between adding and removing a class based on a boolean value.

messageHub.client.notifyAlive = function (aliveMessage, unitId) {
       $('#activity-' + unitId).toggleClass("connection-true",aliveMessage).toggleClass("connection-false", !aliveMessage);

};

Answer 4

toggleClass can be utilized to switch between adding and removing a class based on a boolean value.

messageHub.client.notifyAlive = function (aliveMessage, unitId) {
       $('#activity-' + unitId).toggleClass("connection-true",aliveMessage).toggleClass("connection-false", !aliveMessage);

};

Leveraging SignalR in conjunction with jQuery to dynamically alter the CSS style of a span

Answer №1

Answer №2

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