CODEWITHSUNDEEP
javascriptknockout.js
rlcrews
rlcrews

Reputation: 3562

how to set the visibility of a input field based upon the selected value of a select element within an existing array using knockout.js

I am creating a dynamic filter list that allows a user to add multiple criteria. The list is made up of a select element and two input fields. Initially only one field should display. The second field should only display when the value BETWEEN is selected. I have seen examples of setting the visibility of an element using on select element. Here is what I have so far:

js

function FilterList(Operator, FilterCriteria, FilterCriteriaRange) {
    var self = this;
    self.operator = ko.observable(Operator);
    self.criteria1 = ko.observable(FilterCriteria);
    self.criteria2 = ko.observable(FilterCriteriaRange);
}

function AppViewModel() {
    var self = this;

    self.filterOperators = ko.observableArray([{
        operatorName: "EQUALS",  operatorValue: "=" }, {
        operatorName: "GREATER THAN", operatorValue: ">"}, {
        operatorName: "GREATER THAN OR EQUAL TO", operatorValue: ">="}, {
        operatorName: "LESS THAN", operatorValue: "<" }, {
        operatorName: "LESS THAN OR EQUAL TO", operatorValue: "<=" }, {
        operatorName: "NOT EQUAL TO", operatorValue: "<>" }, {
        operatorName: "NOT LESS THAN", operatorValue: "!>" }, {
        operatorName: "NOT GREATER THAN", operatorValue: "!<" }, {
        operatorName: "BETWEEN", operatorValue: "BETWEEN" }, {
        operatorName: "LIKE",  operatorValue: "LIKE"
    }]);
    //define filter collection
    self.myfilters = ko.observableArray([]);
    self.addFilter = function () {
        self.myfilters.push(new FilterList(self.filterOperators[0]));
    };

    self.inputVisible = ko.computed(function(){
        //retrieve the selected value of the current row and display the second criteria field if the selected value is BETWEEN
        //return self.operator();
    });
}
ko.applyBindings(new AppViewModel());

html

<input type="button" value="Add Filter" title="Add Group" data-bind="click: $root.addFilter" />
<table>
   <tbody data-bind="foreach: myfilters">
     <tr>
     <td>
       <select data-bind="options: $root.filterOperators, value:operator, optionsText:'operatorName'"></select>
     </td>
     <td>
       <input data-bind="value: criteria1" />
      </td>
     <td>
      <input data-bind="value: criteria2, visible: inputVisible() === 'BETWEEN'" />
     </td>
    </tr>
    </tbody>
</table>

Where I am stuck is getting the correct value for the current row that I am interacting with. This link http://jsfiddle.net/rlcrews/R6Kcu/ provides a working fiddle showing the rows being generated I am just stuck on how to derive the selected value from within a select row.

Upvotes: 1

Views: 612

Answers (1)

Chad
Chad

Reputation: 1404

Is this what you're looking for? http://jsfiddle.net/pyvJW/1/.

Since you're looping through myfilters, you have access to the operator field. Since operator is observable, you just needed the parenthesis to access operatorName.

<input data-bind="value: criteria2, visible: operator().operatorName === 'BETWEEN'" />

Upvotes: 1

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