*ngIf does not Set Variable Properly - html

I've been trying to set a variable but it is not rendering on HTML. Here's a simple example:
<div *ngIf="'hello world'; let testVariable">{{testVariable}}</div>
However, the testVairable does not show up on HTML, but instead, the Elements in the inspect printed this:
I have another statement and it is rendering properly. The document variable is from the backend so this statement does not involve any variable setter:
<div *ngIf="document.story_summary " [innerHTML]="document.story_summary"></div>
I was wondering if there's any syntax that I miss?

There is an issue in your syntax. You need to put the testVariable first in your *ngIf, if not, it will always set as true. Also, ngIfElse accepts template instead of just a string, so you need to add a template to cater for your else. See the code below:
<div *ngIf="testVariable; else hello_world">{{testVariable}}</div>
<ng-template #hello_world>hello world...</ng-template>

Yes, there is an issue in your syntax your html format should be like this
<div *ngIf="testVariable; else hello_world">{{testVariable}}</div>
<ng-template #hello_world>hello world...</ng-template>
else part will be working in <ng-template>else part</ng-template>

Related

How to pass html element into rowDragText callback

I am not even sure if what I am trying to do is possible. I want to present the "floating" DOM element created when dragging a row as something more than just text. Seems like when I try to use html code as the returned value it is rendered as text rather than html:
rowDragText: function(params) {
return `<div [innerHTML]=${params.rowNode.data.RULE_NAME}></div>`;
}
This is what happens:
There is public static GHOST_TEMPLATE defined in dragAndDropService.ts.
You can try modifiying that template and perhaps also inspect the createGhost function nearby.
rowDragText probably not used with this method...

Angular 8 template reference variable scope unclear

I have given a name using the #var notation to an angular component (app-backtester-chart) created by me, but I don't understand why I don't seem to be able to reference it outside of the div it is in?
I'm clearly missing something here...
{{chartcmp.width}}
<div class="row">
<div class="col" *ngIf="thisStrategy">
{{chartcmp.width}}
<app-backtester-chart #chartcmp
[inputStrategy]="thisStrategy"
[showBenchmark]="showBenchmark">
</app-backtester-chart>
</div>
</div>
The first {{chartcmp.width}} generates an error: Cannot read property 'width' of undefined
So why does the second one inside the div works, and correctly displays the width?
From the Angular documentation (Template reference variables):
You can refer to a template reference variable anywhere in the component's template.
I can't find an explanation anywhere. Any help would be greatly appreciated.
It's beacause of the *ngIf. You can't access a template reference variable if it's not rendred.
I think it's because your *ngIf if you're doing an ngIf all div inside are not constructed as well as your variable ^^
Try this for first one
{{chartcmp === null? "" : chartcmp.width}}

Angular2 function call from html element with no load event (or similiar)

I am new to Angular and have run into a problem that seems to have a javascript work around but they aren't very elegant.
I have a model with an array property. I ngfor the list property to build some html selection options. This is all working nicely. The problem comes when I am trying to set default value...the html elements don't have a load event.
I tried numerous html elements and they don't appear to have a load event either but I certainly could be doing it wrong.
I have seen a solution to put javascript tag right after the html and I could do that but I was really looking for a more elegant way in Angular.
I saw this SO post and thought that was my answer but there is a warning given that I agree with and thus it doesn't appear to be a good solution.
Regardless I tried it just to see if it would work and I got:
Failed to execute 'setAttribute' on 'Element': '{{loadDefaults()}}' is not a valid attribute name
<span {{loadDefaults()}} ></span>
So how can I fire an AS2 function in the component to load the default values?
HTML (btw this is NOT a full page load so there is no body tag):
<tr>
<td *ngFor="let loc of locOptions;">
<span>{{loc.text}}</span>
<input type="radio" name="radiogroup" [value]="loc.value" (change)="onSelectionChange(loc.value)">
</td>
</tr>
Edit
I thought perhaps mistakenly that ngoninit would fire too soon...before the html elements are rendered.
So perhaps what is being suggested is that I add a boolean is default to the model and bind THAT as the element is rendered.
In your ngonit function set this.locOptions to your default values. The value can be changed later on in any function and the change will be reflected in the view. Hope this helps you.
You should use ngOnInit to init you data, and call retrieve your data from your component :
defaults : any;
ngOnInit {
this.defaults = loadDefaults();
}
loadDefaults() {
//get data
}
HTML :
<span>{{defaults}}</span>

Angular 1.4.8 inner ng-show cause an error when used in custom directive root element

I got an error when i put a nested ng-show attributes for custom directive,
one attribute in the markup of the directive and the second inside the root element of the directive template.
My real scenario are complex so i will simplify it to this example:
Suppose i have my-custom-directive below which already contains ng-show:
<my-custom-directive ng-show="someValue >= 5"></my-custom-directive>
And then the template of 'my-custom-directive' look like this:
<div ng-show="options != null">My Custom Directive</div>
Those multiple ng-show together cause an error.
if i remove one of them or move the inner ng-show at least one level deeper in it's dom tree the error gone (it's happen when it's location is on the root template element).
this error tested on angular v1.4.8.
Is this angular bug? or there is a reasonable explanation for this behavior?
here is the Plunker example:
http://embed.plnkr.co/ZTZVcfc5bfmjPo9t0Isw
Thank you in advance,
Menachem
Because the directive has replace: trueit is trying to merge the two ng-show values together resulting in an error. The simplest solution I believe is to just do replace: false
Or you can inject the value via isolate scope and use a single ng-show value within the directive. I believe this is considered the cleaner solution.
Example: http://plnkr.co/edit/5oc8c1Hrz8N1F2klCio7?p=info
scope: {
someValue: '=someValue'
}

Binding dynamically within an ng-repeat expression

For a TV Guide, I am trying to create a dynamic expression within an ng-repeat directive as follows:
<div ng-repeat="programme in programmes['{{channel}}-wed-jan-14']" alt="{{channel}}">
{{channel}} in my controller should evaluate to something like "eTV". The binding is working fine with the alt="{{channel}}" instance but not with the array instance. Angular simply serves up the line of code commented out. If I hardcode the "eTV" string in place of the {{channel}}, it works fine.
Am I trying to ask Angular to do what it is not designed for, or is it possibly my array handling which is dodgy?
Okay, not sure if I just asked a dumb question, but in the absence of responses, I managed to figure out a solution by writing a filter as follows:
Template:
<div ng-repeat="programme in programmes | getChannelDay:channel:dayString" alt="{{channel}}">
Controller filter:
app.filter('getChannelDay', function() {
return function(programmes, channel, dayString) {
return programmes[channel + dayString];
};
});
The issue with my initial problem
<div ng-repeat="programme in programmes['{{channel}}-wed-jan-14']" alt="{{channel}}">
is that I was trying to put {{channel}} inside the expression, but that is the format for markup.
I tried to use the following instead:
<div ng-repeat="programme in programmes['channel + daystring']" alt="{{channel}}">
but I am doing something wrong here. I am pretty sure there is a way to get this to work - if anyone knows, please comment.