I am working on a drop down menu within a TR .. I have true, false or none as the value that I receive from server and I want that to change the drop down option as in example below.
The first one is working but I want the second one to function as the first one
Example is here: http://jsfiddle.net/3xLgJ/
This is my HTML:
<div data-bind='text: incomingValue'></div>
<select data-bind="value: incomingValue">
<option value="true">Yes</option>
<option value="false">No</option>
<option value="none">Don't Know</option>
</select>
How can I implment this as above as this is within a tr and to function as above
<select data-bind='options: yesno, value: incomingValue'/>
Here is my knockout
var myModelView = function () {
self = this;
self.yesno = ko.observableArray(['Yes', 'No', 'Don\'t know']);
self.incomingValue = ko.observable('none');
};
var moView = new myModelView();
ko.applyBindings(moView);
Thanks
Thanks
The best solution is probably to slightly reconstruct the view model to use objects instead of simple strings:
// Create a "class" that represents an option
var Option = function(id, caption) {
this.id = id;
this.caption = caption;
};
Now you populate the observable array with objects constructed from this function:
self.yesno = ko.observableArray([
new Option('true', 'Yes'),
new Option('false', 'No'),
new Option('none', 'Don\'t know')
]);
You can use the "optionsText" binding to correctly bind these objects to the markup:
<select data-bind="options: yesno,
optionsText: 'caption',
value: selectedItem"></select>
If you receive a string "none" from the server, you need to find the object representing this option:
var incomingValue = 'none';
// Find the first object that is a match in the observable array "yesno"
var incomingItem = ko.utils.arrayFirst(self.yesno(), function(item) {
return item.id == incomingValue;
});
self.selectedItem = ko.observable(incomingItem);
When displaying the selection somewhere else you'll need to consider that the selection is represented by an object:
<div data-bind='text: selectedItem().caption'></div>
Demo: http://jsfiddle.net/3xLgJ/2/
You need to use the optionsText and optionsValue bindings. You'll need to make an observable array of values and text:
self.yesno = ko.observableArray([
{value:"true",text:"Yes"},
{value:"false",text:"No"},
{value:"none",text:"Don't Know"}]);
then, you need to do something like this in your html:
<select data-bind="options: yesno2, optionsText: 'text',optionsValue: 'value', value: incomingValue"></select>
See here for a working example
Related
I have a page that populates its fields(dropdowns and textboxes) from the DB when the page loads via VIEWDATA object from controller.
I am using KnockoutJS for data-binding, below is the scenario
HTML & JS(dropdown)
#if (Filter!= null)
{
<select data-bind="options: RsnAdmAct,
value: selectedRsnAdmAct,
optionsCaption:'Choose...',
optionsValue:'RsnAdminActionID',
optionsText:'RsnAdminActionDescp',
optionsAfterRender: function()
{
setOptionRSN(#Filter.RsnForAdminAction);
}">
</select>
}
self.RsnAdmAct = ko.observableArray([]);
self.selectedRsnAdmAct = ko.observable();
$.getJSON("GetRAA", null, function (data) {
self.RsnAdmAct(data);
});
self.selectedRsnAdmAct = ko.observable();
self.setOptionRSN = function (x) {//reason for admin action dd
self.selectedRsnAdmAct(x);
};
this does update the drop-down with the assigned value "X".
But the same does not assign value for the text-boxes as below
HTML & JS(textbox)
#if (#Filter != null)
{
<input placeholder="Downstream"
data-bind="value: DownStream,
optionsAfterRender:function()
{
setOptionDstream(#Filter.DownstreamNumber);
}">
}
self.DownStream = ko.observable();
self.setOptionDstream = function (x) {//down stream number
self.DownStream(x);
};
optionsAfterRender applies to options; a text input has no options. Setting the value of DownStream will set the value of the text box, because that's how the value binding works.
I tried to search for a proper way to do this but below is the way it works and no other alternative worked.I had to move the function which assigns the value to the texbox observable into the options after render attribute of the drop down as below
#if (Filter!= null)
{
<select data-bind="options: RsnAdmAct,
value: selectedRsnAdmAct,
optionsCaption:'Choose...',
optionsValue:'RsnAdminActionID',
optionsText:'RsnAdminActionDescp',
optionsAfterRender: function()
{
setOptionRSN(#Filter.RsnForAdminAction);
setOptionDstream(#Filter.DownstreamNumber);
}">
</select>
}
This is the only way it worked for me.Thank you for the posts and comments
I'm using Knockout 3.2 and i'm trying to display a multiple select dropdown with some selected values, but the values are not being selected. The problem is that KO does not populate the 'value' attribute of the options:
<select data-bind="options: availableCountries, selectedOptions: chosenCountries, optionsText: 'name'" size="5" multiple="true">
<option value="">France</option>
<option value="">Germany</option>
<option value="">Spain</option>
</select>
VM:
var viewModel = {
availableCountries : ko.observableArray([{name:'France'}, {name:'Germany'}, {name:'Spain'}]),
chosenCountries : ko.observableArray(['Germany'])
};
If instead of object i turn availableCountries into a simple strings array, it works.
You can see a live sample here
var viewModel = {
availableCountries : ko.observableArray([{name:'France'}, {name:'Germany'}, {name:'Spain'}]),
chosenCountries : ko.observableArray(['Germany'])
};
['Germany'] is not {name: 'Germany'}!
And also if you, would write chosenCountries : ko.observableArray([{name: 'Germany'}]), this would lead to two different objects, with the same property name and the value 'Germany'.
var viewModel = (function() {
var self = {};
self.availableCountries = ko.observableArray([{name:'France'}, {name:'Germany'}, {name:'Spain'}]);
self.chosenCountries = ko.observableArray([self.availableCountries()[1]]);
return self;
})();
ko.applyBindings(viewModel);
I changed the viewModel, to an instand called function which returns the viewModel.
(function () {...})()<-call
http://jsbin.com/monasijufaya/1/edit?html,js,output
I have this Javascript code for a dropdown list
$('#TravelG').append("<option value selected>Select TravelG</option>");
for (var i = 0; i < Travel.length; i++) {
$('#TravelG').append("<option value='" +
Travel[i].Id + "'>" + Travel[i].Name + "</option>");
}
I need to rewrite the above code in knockout as in I have this observable array,
viewModel.Travelname = ko.observableArray([]);
I need to populate this Travelname property of viewmodel as name , value pair and Travel is the object that contains the data. So that I can tie this Travelname property of a viewmodel to a dropdown. How do I achieve this ?
As correctly mentioned in comments by #hunch_hunch, you should use knockout options binding for this.
Suppose your Travel model looks like this:
function Travel(id, name) {
this.Id = id;
this.Name = name;
}
Then in your view model you have your observableArray with collection of Travel objects (this refers to view model):
this.Travelname = ko.observableArray([new Travel(1, 'Moscow'), new Travel(2, 'Paris'), new Travel(3, 'San Francisco')]);
The final part is your markup, which should be something like this:
<select data-bind="options: Travelname, optionsText: 'Name', optionsValue: 'Id', optionsCaption: 'Select travel...'"></select>
Here is final working demo. I've added simple functionality to add items to the list, so you would see how to do that.
I have this code and information:
$scope.options = [
{ id: 1, label: "My label" },
{ id: 2, label: "My label 2" }
];
$scope.selected = 2;
<select ng-options="opt.label for opt in options" ng-model="selected">
<option value="">Select one</option>
</select>
However, the options are created like this:
<select ng-options="opt.label for opt in options" ng-model="selected">
<option value="">Select one</option>
<option value="0">My label</option>
<option value="1">My label 2</option>
</select>
How can I set the selected option to My label 2? I know it can be done:
$scope.selected = $scope.options[1];
But my problem is that option is created in a directive, and at that moment I don't know 1) how many values has $scope.options, nor 2) what is the index of the selected option in database. The only thing I know is the id (which is in the object).
The html of my directive is something like this:
<select ng-switch-when="select" ng-model="form.model[element.model]" ng-options="{{element.rule}}"></select>
Where element.rule is:
rule: "role.role for role in element.options"
And element.options has the array with options, and form.model[element.model] has the id of the option selected.
How can I get the index of the element with ID X in the array $scope.options? I'm very sure that will give me the solution, but I don't know how to do it...
Just set the correct model value when initiating the controller. You can easily get the correct array value if you know the ID by using a filter:
$scope.selected = $filter('filter')($scope.options, {id: 2})[0];
The issue with your code as I see it is that the 'selected' value coming out of your database is the ID of the object selected and not the object itself. This is fine but because of that difference you can't simply set
$scope.selected = 2 //assuming 2 is the value coming from your database
because the value '2' does not exist in your option array. The Object with an ID of 2 does.
If you can always guarantee the options you have in the option array are from 1-n and in that order, you can accomplish this by simply using this instead:
$scope.options = [
{ id: 1, label: "My label" },
{ id: 2, label: "My label 2" }
];
var selectedIdFromDatabase = 2;
$scope.selected = $scope.options[selectedIdFromDatabase-1];
If you can't make that guarantee (and even if you can for now, it may not be a good idea to make that assumption in your code) you'll need iterate over the array of objects you have to identify the object with an ID of the selectedId from your database.
The answer to this question has a great write-up about the type of data-processing you'll need to do and a lot more information about javascript objects in general.
I have a select with the attribute multiple. For each option in the select I want the title attribute set (which shows a tooltip). I also want to retrieve the selected options as an array of objects. I managed to get what I want except for the fact that the selected options doesnt return an array of objects but an array of valueTexts. I can't figure out how I get objects in that array.
This is the code I got so far:
HTML:
<select multiple style="width: 150px;" size=15
data-bind="foreach: options, selectedOptions: selectedOptions">
<option data-bind="text: Name, attr: { 'title': Name}"></option>
</select><br />
<button data-bind="click: showSelectedOptions">Show selection</button>
Javascript:
function Option(id, name){
var self = this;
self.Id = id;
self.Name = name;
}
function ViewModel(){
var self = this;
self.options = ko.observableArray([
new Option(0, "NormalText"),
new Option(1, "AnotherText"),
new Option(2, "WaaaaaaaaaaaaaaaayTooLongText")
]);
self.selectedOptions = ko.observableArray([]);
self.showSelectedOptions = function(){
alert(self.selectedOptions());
//what I would like to have:
//if (self.selectedOptions().length > 0)
// alert(self.selectedOptions()[0].Name);
}
}
ko.applyBindings(new ViewModel());
And the fiddle link for demonstration: http://jsfiddle.net/c63Bb/1/
What do I need to add or change so the array selectedOptions contains objects instead of strings?
Try your html like this
<select
data-bind="
options: options,
selectedOptions : selectedOptions,
optionsText: 'Name',
optionsCaption: 'Choose...'
"
size="5" multiple="true"></select>
Demo
See the console for output
EDITS :
To add attributes to option you need to use optionsAfterRender.
This is available only in version 3.1.0. I noticed your fiddle is using 3.0.0.
<select
data-bind="
options: options,
selectedOptions : selectedOptions,
optionsText: 'Name',
optionsAfterRender: $root.setTitle
"
size="5" multiple="true"></select><br />
<button data-bind="click: showSelectedOptions">Show selection</button>
And create a fnction
self.setTitle = function(option, item) {
option.title = item.Name
}
Demo
Reference
See Note 2
Similar to #MuhammadRaheel, I used optionsAfterRender:
<select data-bind="optionsAfterRender: myFunc, ...">
But I needed to use ko.applyBindingsToNode:
var self.myFunc = function(option, item) {
ko.applyBindingsToNode(option, { attr: { title: 'Tooltip!' } }, item);
}
Use options and optionsText bindings instead of foreach:
<select multiple style="width: 150px;" size=15
data-bind="options: options, optionsText: 'Name', selectedOptions: selectedOptions">
<option data-bind="text: Name, attr: { 'title': Name}"></option>
</select>
Here is demo: http://jsfiddle.net/p5E8y/