Bind selected value to Multi Select ListboxFor control using AngularJS

I’m facing issues in below scenario, Can any one please guide me.

Scenario:
Get the comma separated Ids from DB which already user entered and split the values then bind values into Multi Select List box control in edit mode.

I tried the following piece of code to achieve it, but its not working for me.

@Html.ListBoxFor(c => c.ClientDemographicHospitalId, new MultiSelectList(Model.Hospitals, "Value", "Text"), new { ng_model = "hospitalDropdownList", @class = "HospitalListbox", style = "width:65%" })

var lstSelectedIDs = employee.ClientDemographicHospitalId;
var arySelectedID = lstSelectedIDs.split(",");

for (var i = 0; i <= arySelectedID.length; i++) {
    $scope.hospitalDropdownList.append($('<option></option>').val(arySelectedID[i].Value).html(arySelectedID[i].Text));
}

Attached the screenshot.

Code:

Control:

Source: AngularJS