How can i add selected member in duallis box?

Question

hello guys 

 i have a bootstrapDualListbox and i have all options on left side and as user select then selected option shift in rigth side , 

 i have a query how can i added options in right side which are selected when i want to edit. 

i want to when user edit its options then edit forms show selected and non selected options. my code is below which are on MVC plsea guide me 

 

<div class="dual-list-box-area mg-b-40">
                        <div class="container-fluid">
                            <div class="row">
                                <div class="col-lg-12">
                                    <div class="sparkline10-list shadow-reset">

                                        <div class="sparkline10-graph">
                                            <div class="basic-login-form-ad">
                                                <div class="row">
                                                    <div class="col-lg-12">
                                                        <div class="dual-list-box-inner">
                                                            @Html.DropDownListFor(model => model.SelectList, ViewBag.Leaves as IEnumerable<SelectListItem>, new { @class = "form-control dual_select", @multiple = "multiple" })

                                                        </div>
                                                    </div>
                                                </div>
                                            </div>
                                        </div>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>

below is snpshot which i want require.