A simple way to subscribe and/or broadcast from anywhere in an app to anywhere else.

Basically, I needed a simple way to send out global messages not knowing what components would be loaded and didn't want to deal with injecting this anywhere in older components.  With a little messing around with some online guides (sorry I don't remember which ones) I came up with the following:

broadcast.service.ts

import { Injectable } from "@angular/core";
import { Subject } from "rxjs/Subject";

@Injectable()
export class BroadcastService {

    static instance: BroadcastService;
    static isCreating: Boolean = false;

    private broadcastMessageSource = new Subject<string>();
    broadcastMessage$ = this.broadcastMessageSource.asObservable();
    
    constructor() {
        if (!BroadcastService.isCreating) {
            throw new Error("You can't call new in Singleton instances");
        }
    }

    static getInstance() {
        if (BroadcastService.instance == null) {
            BroadcastService.isCreating = true;
            BroadcastService.instance = new BroadcastService();
            BroadcastService.isCreating = false;
        }
        return BroadcastService.instance;
    }

    broadcastMessage(modal: string) {
        this.broadcastMessageSource.next(modal);
    }
}

Then simply make sure to import it where you need it, and send out a broadcast:

BroadcastService.getInstance().broadcastMessage('message-i-care-about');

Where you need to,  subscribe in the constructor (or ngOnInit):

BroadcastService.getInstance().broadcastMessage$.subscribe(this.receiveBroadcastMessage.bind(this));

And deal with the broadcast however you will:

receiveBroadcastMessage(broadcast: string): void {
    console.log('broadcast received: ' + broadcast);

    // I generally run it through a switch to see if its something this component cares about
    switch (broadcast) { 
        case 'message-i-care-about': doSomething(); break;
    }
    // or just ignore it
}

There you go, just sent and received a global broadcast message.

Inside my service fabric, I was creating a ServiceProxy to call another part of the fabric which I had working in multiple other places in my code like this:

var uri = new Uri("fabric:/MyNameSpace.MyClass");
var proxy = ServiceProxy.Create<ISomeInterface>(uri);
proxy.DoSomething(someString, someObjectCollection);

And it worked perfectly fine, next I tried with a different interface and it just silently failed, literally the exact same setup, but a new interface.

public interface ISignalRelay : IService
{
    Task Broadcast(string group, string message, object details);
}

Then my code:

var uri = new Uri("fabric:/MyNameSpace.MyClass");
var signalRelay = ServiceProxy.Create<ISignalRelay>(uri);
signalRelay.Broadcast(group, message, nonPrimitiveObject);

When stepping through the code, it would work fine until I hit Broadcast() and then just continue on, but that code was never hit.  From what I deduced, it was the ability of the proxy to deal with the base object class when it was passed something that was not a primitive type.

I was able to work around this as I was able to pass in a serialized string version of the object instead, but this is definitely a limitation of the way fabric works.  As an FYI, I tried generics, but you can not use the cross class fabric structure with generics (I forget the actual exception, but it's explicitly stated you cannot).  

If anyone has a way around this, or a better understanding, I would love to hear it.  Otherwise, I hope this saves someone from bashing their head on the desk all day like it did me.

manually creating a controller and running its action does not run as the logged in user

public T RunAsCurrentUser(
    T controller, RouteData routeData = null) 
        where T : ControllerBase
{
    var newContext = new ControllerContext(
        new HttpContextWrapper(
            System.Web.HttpContext.Current), 
            routeData ?? new RouteData(), controller);
    controller.ControllerContext = newContext;
    return controller;
}

var someController = RunAsCurrentUser(
    new Some.NameSpace.SomeController());
var result = someController.SomeAction();

possible reason you may find this nondescript error

TypeError: u is undefined

$('#grid').kendoGrid();

working locally, but not on deploy

Styles/Javascript not rendering at all

bundles.Add(new StyleBundle("~/Styles/Metro").Include(
            "~/Styles/Metro/metro-bootstrap.css",
            "~/Styles/Metro/metro-ui-icons.css"));

@Styles.Render("~/Styles/Metro")

bundles.Add(new StyleBundle("~/Styles/MetroCss").Include(
            "~/Styles/Metro/metro-bootstrap.css",
            "~/Styles/Metro/metro-ui-icons.css"));

@Styles.Render("~/Styles/MetroCss")

@Styles.Render("~/Styles...")

@Scripts.Render("~/Scripts...")

Images or Fonts not rendering

common error in Kendo UI that has a simple solution

TypeError: n.slice is not a function

{
    "TrackingModels":[
        {"Id":17,"Name":"Bill"},
        {"Id":17,"Name":"Bob"}
    ]
}

{[
    {"Id":17,"Name":"Bill"},
    {"Id":17,"Name":"Bob"}
]}

frustrating profiler error when you aren't actually using a profiler

The other day I was troubleshooting an Azure problem, and I had turned on my profiler:

The Fix

Not to say there is not a better fix (I tried all I could find elsewhere, nothing seemed to relate to my specific problem) but here is what I ended up doing. Simply delete your deployment, and re-publish. This must re-set whatever turning on your profiler sets.

simple way to move an element from A to B

<ul id="A">
    <li id="L1">Stan</li>
    <li id="L2">Arnold</li>
</ul>
<ul id="B">
</ul>

(function ($) {
    $.fn.moveTo = function (selector) {
        return this.each(function () {
            var element = $(this).detach();
            $(selector).append(element);
        });
    };
})(jQuery);

$('#L1').moveTo('#B');

<ul id="A">
    <li id="L2">Arnold</li>
</ul>
<ul id="B">
    <li id="L1">Stan</li>
</ul>

$('li').moveTo('#B');

<ul id="A">
</ul>
<ul id="B">
    <li id="L1">Stan</li>
    <li id="L2">Arnold</li>
</ul>

if you have tried to serialize a CheckBoxFor from MVC to JSON, you will notice that you get two inputs, and it can mess up the data you are sending

public static string GetPropertyName<TModel, TValue>
    (Expression> exp)
{
    MemberExpression body = exp.Body as MemberExpression;
    if (body == null)
    {
        UnaryExpression ubody = (UnaryExpression)exp.Body;
        body = ubody.Operand as MemberExpression;
    }
    return body.Member.Name;
}

public static MvcHtmlString CheckBoxForJson<
    TModel, TValue>(this HtmlHelper<TModel> helper, 
    Expression<Func<TModel, TValue>> expression)
{
    string propName = GetPropertyName(expression);
    string html = "<input type=\"checkbox\" name=\"" 
        + propName + "\" id=\"" 
        + propName + "\" value=\"true\" />";
    return MvcHtmlString.Create(html);
}

@Html.CheckBoxForJson(x => x.SomeBool)

nothing revolutionary, just helpful in some debug situations

alert(JSON.stringify(data, null, 4));