Passing parameter from Knockout template to modal

Question

In this code example I'm looking for a way to pass parameters from data in Knockout's template into Knockout's data-bind that should ultimately appear in modal window.

The result should be a modal window that displays a participant's name based on which participant is to be deleted.

Right now I have to enter the names manually, what should be done to have them automatically binded?

var viewModel = function() {
  this.showModal = function() {
    console.log("Showing modal");
    $('#modal').modal('show');
  }
  this.buyer = {
    name: 'Franklin',
    credits: 250
  };
  this.seller = {
    name: 'Mario',
    credits: 5800
  };
};
ko.applyBindings(new viewModel);

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" rel="stylesheet" />
<link href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>

<div data-bind="template: { name: 'person-template', data: buyer }"></div>
<div data-bind="template: { name: 'person-template', data: seller }"></div>

<script type="text/html" id="person-template">
  <h3 data-bind="text: name"></h3>
  <p>Credits: <span data-bind="text: credits"></span>
  </p>
  <button data-bind="click: $root.showModal" class="btn">Delete</button>
</script>

<div id="modal" class="modal fade" tabindex="-1" role="dialog">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span>
        </button>
        <h4 class="modal-title">Delete item</h4>
      </div>
      <div class="modal-body">
        <p>Really delete Franklin?</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
        <button type="button" class="btn btn-primary">Delete</button>
      </div>
    </div>
    <!-- /.modal-content -->
  </div>
  <!-- /.modal-dialog -->
</div>
<!-- /.modal -->

Answer 1

First, you need to make the name something KO manages:

<p>Really delete <span data-bind="text: deleting"></span>?</p>

Give yourself an observable for that in your view model:

this.deleting = ko.observable(null);

Then update showModal to update an observable:

this.showModal = function(deleting) {
  this.deleting(deleting.name);
  console.log("Showing modal");
  $('#modal').modal('show');
};

Then, since you're using $root.showModal, this will be incorrect, but we can addres that with bind:

<button data-bind="click: $root.showModal.bind($root)" class="btn">Delete</button>

Live Example:

var viewModel = function() {
  this.showModal = function(deleting) {
    this.deleting(deleting.name);
    console.log("Showing modal");
    $('#modal').modal('show');
  };
  this.deleting = ko.observable(null);
  this.buyer = {
    name: 'Franklin',
    credits: 250
  };
  this.seller = {
    name: 'Mario',
    credits: 5800
  };
};
ko.applyBindings(new viewModel);

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" rel="stylesheet" />
<link href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<div data-bind="template: { name: 'person-template', data: buyer }"></div>
<div data-bind="template: { name: 'person-template', data: seller }"></div>

<script type="text/html" id="person-template">
  <h3 data-bind="text: name"></h3>
  <p>Credits: <span data-bind="text: credits"></span>
  </p>
  <button data-bind="click: $root.showModal.bind($root)" class="btn">Delete</button>
</script>

<div id="modal" class="modal fade" tabindex="-1" role="dialog">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span>
        </button>
        <h4 class="modal-title">Delete item</h4>
      </div>
      <div class="modal-body">
        <p>Really delete <span data-bind="text: deleting"></span>?</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
        <button type="button" class="btn btn-primary">Delete</button>
      </div>
    </div>
    <!-- /.modal-content -->
  </div>
  <!-- /.modal-dialog -->
</div>
<!-- /.modal -->