Below is the HTML snippet for a button that I would like to be disabled while no files, from a UI list of files, are selected:
<button id="downloadButton" disabled.bind="selectedFileCount() == 0" click.trigger="downloadFiles()" type="button">Download Selected</button>
The conditional function for whether the button is disabled or not:
selectedObjects = [];
selectedFileCount() {
return this.selectedObjects.length;
}
When a file is selected, the following is triggered:
rowSelected($event) {
this.selectedObjects.push($event.detail.row);
}
I know that rowSelected works properly as I can console.log(selectedObjects.length) and get the correct length. I know that selectedFileCount() works because I can return boolean values which are reflected in whether the button is disabled or not.
It appears that once disabled.bind is set on DOM load, it cannot be changed. Is this assumption correct? What should I do?
Aurelia treats any function calls in a binding as being pure function calls. Since your selectedFileCount function doesn't take any parameters, this means that Aurelia assumes the output value of the function will never change. That is why your disabled binding never changes.
My recommendation for how to fix it is to simply put the check in the binding.
<button id="downloadButton" disabled.bind="selectedObjects.length == 0"
click.trigger="downloadFiles()" type="button">
Download Selected
</button>
Related
I have multiple elements on a page that are triggering a load of select2 to the element. I'm trying to conditionally check if the element has a certain class, and if so add the tag option; otherwise do not. I thought something like this would work, but it's not:
$('.element_to_add_select_two_on').select2({
tags:function(element) {
return (element.className === 'classname_i_am_targeting');
},
});
What am I missing here? I'm subjecting myself to the following buffoonery to get this to target and load:
$('.element_to_add_select_two_on').each((index,element) => {
let showTags = false;
if ($(element).attr('class').split(' ').includes('classname_i_am_targeting')) {
showTags = true;
}
$(element).select2({
tags:showTags,
});
});
There are a few problems with your first attempt. First, you are defining tags as a function when what you want is the result of the function, since tags needs to be defined as a boolean true or false. The other is that inside your .select2() call, you do not have access to the calling element $('.element_to_add_select_two_on') in the way that you think. It isn't an event that you are listening on, it's a function call that wants an object passed with its configuration.
You conveyed that your second method works, but it can be simplified with the jQuery hasClass() function:
$('.element_to_add_select_two_on').each((index, element) => {
$(element).select2({
tags: $(element).hasClass('classname_i_am_targeting'),
});
});
There is a much simpler way to do all of this, however, and it is much more flexible and already built into select2 via the way of data-* attributes (note, you need jQuery > 1.x). You can simply add data-tags="true" to any of your select elements with which you want tags enabled. These will override any configuration options used when initializing select2 as well as any defaults:
<select data-tags="true">
...
</select>
<script type="text/Javascript">
function phase2Function(){
document.getElementById("0").onclick = buttonChangeFunction();
}
function buttonChangeFunction(){
document.getElementById("1").disabled = "true";
}
</script>
<button id="0" onclick="numberFunction(0)">0</button>
<button id="1" onclick="numberFunction(1)">1</button>
I have a problem with the above code that makes the "buttonChangeFunction" work without me clicking 0. The project im working on is a calculator, where after you press a math operator, it starts phase2Function. Edit: The Question Has been Answered, but I was wondering what to do if I actually want to put something in between the parentheses of buttonChangeFunction?
You need to remove the parenthesis after buttonChangeFunction in phase2Function.
What you are trying to do is make buttonChangeFunction fire each time the button with the ID of '0' is clicked.
Instead, what you're actually doing, is calling buttonChangeFunction, getting back an undefined result (since the function doesn't return anything) and then setting the click handler of the id=0 element to this undefined result.
So, simply change:
document.getElementById("0").onclick = buttonChangeFunction();
to
document.getElementById("0").onclick = buttonChangeFunction;
I'm wondering, is there a possibility to have databindings "out of" a template? Say I have a <template/>-Tag somewhere which I put into the slot of a different component - that component stamps it to its context. Then I want to bind data from the root element to the <template/>-Tag. Also, event bindings (on-x-changed) don't work, because you can't assign a function which is defined in the hosting component. Any ideas?
Example:
... host
{{boundData}}
<binding-component>
<template>
{{boundData}}
</template>
</binding-component>
I don't see changes when I observe boundData in the hosting component. Is there a way to get around this? Or is firing a custom event my only chance?
If you are looking for binding a property outside of polymer something like from index.html you may bind value with element. an example ; index.html
<dom-bind>
<template>
<binding-component bound-data="{{boundData}}"></binding-component>
</template>
</dom-bind>
<script>
// set a value a string, Number or Object etc.
// Optionally wrap this code into a listener ie;
// window.addEventListener('load', e=> { ...below code ... })
var boundData= document.querySelector('dom-bind');
boundData = {} //
</script>
Now in your binding-component element has a property as boundData
hope its helps or provide more code to understand better.
I've made it work the way dom-if does it, too. Like in dom-if (reference), I'm creating a Templatize-instance which then uses forwardHostProp to handle the "inside"-properties
this.__ctor = Templatize.templatize(template, this, {
mutableData: true,
forwardHostProp(prop, value) {
// handling item updates, item being the only property
// from within the binding component
// everything else is automatically bound by templatize
this.set(prop, value);
this.update(this.item);
},
});
this.__instance = new this.__ctor();
this.root.appendChild(this.__instance.root);
This all happens in connectedCallback.
Because the Templatize-instance is passed this, it's bound to the current context as well.
Good luck!
I'm using a checkbox to create a toggle switch as shown in this tutorial
The switch lives in a form where questions can be added dynamically. On submission the form posts as array of each answer back to the page to be processed however as the off switch doesn't pass a value back to the form the answers get out of sync with the answers for the other text fields. Is there any way to set a value for the off switch, i.e. when a check box is left unchecked?
I've tried to use the following to set my off checkboxes to off however it just seems to animate all the switches to on on form submission, anyone any ideas as to what I'm doing wrong?
$('form').submit(function(e){
var b = $("input:checkbox:not(:checked)");
$(b).each(function () {
$(this).val(0); //Set whatever value you need for 'not checked'
$(this).attr("checked", true);
});
return true;
});
You probably want to use Javascript to set a value for each checkbox "switch" in one of two ways:
Option 1: in the html of the switch elements/checkboxes, set the value attribute to zero by default. Then add a javascript click handler for the toggle to check its current value and toggle to the opposite state/value.
Option 2: add Javascript to the form's submit handler (on submit) that checks for any switch elements which have no values and set them to zero before processing form.
Either way should pass a value at all times, and your form should be able to keep track of all input states.
This snippet did the trick, as Anson suggested this finds all the checkboxes and sets them to either on or off on form submission:
$('form').submit(function () {
$(this).find('input[type="checkbox"]').each( function () {
var checkbox = $(this);
if( checkbox.is(':checked')) {
checkbox.attr('value','1');
} else {
checkbox.after().append(checkbox.clone().attr({type:'hidden', value:0}));
checkbox.prop('disabled', true);
}
})
});
I stuck with the inline validation in the kendo grid.
I don't want to validate after losing focus. I want to validate immediately after typing. So I start using the HTML validator. It works pretty well but the problem is I cant answer these two questions:
which event set the input from valid to invalid.
which event displays the error message.
My Current work: https://dojo.telerik.com/OSONo/56
which event set the input from valid to invalid.
...
which event displays the error message.
Just run your kendoValidator with validator.validate();
The error messages are also set with validate().
Something like this should work:
$(document).on('input propertychange', function() {
validator.validate();
});
The warning seems to be hidden behind some elements, so you can also add the folowing errorTemplate to your kendoValidator:
errorTemplate: '<div class="k-widget k-tooltip k-tooltip-validation" style="margin: 0.5em; display: block;"><span class="k-icon k-i-warning"></span>#=message#<div class="k-callout k-callout-n"></div></div>'
And the whole solution:
https://dojo.telerik.com/OSONo/66
Solved my Problem on my Own. I will edit the post so you can see what i mean but first i just give the dojo projcet.
https://dojo.telerik.com/OSONo/64
my edit:
I am sorry for my previous anwser, i just want to give him my solution i mention in my comment.
In my solution i created an event listener, how listen to all input elements. When something has changed it, saves the current cursor position (its import for ie support) and after this it trigger my "change" event. The "change" event check if it is valid or invalid. If it is invalid the kendo validator shows imidently the error-message (not as default by a blur event).
var ValidierungCheckClass = (function () {
return {
AllDOMElements: function () {
$('body').on('input', function () {
var myActiveElement = $(':focus');
if ((myActiveElement) && (myActiveElement.context.activeElement.nodeName.toLowerCase() !== "body")) {
var myActiveDOMElement = myActiveElement[0],
start = myActiveDOMElement.selectionStart, //just for IE Support
end = myActiveDOMElement.selectionEnd; //just for IE Support
myActiveElement.trigger("change");
myActiveDOMElement.setSelectionRange(start, end); //just for IE Support
}
})
}
}
});
The change event is allready created from kendo so you dont have to write your own.
At least you have to call the method when creating the website.
<script>
ValidierungCheckClass().AllDOMElements();
</script>
This is my Solution to my problem.
best regards.