var pageSize = 10;
    $('#Cliente').select2(
    {
        minimumInputLength: 0,
        allowClear: true,
        ajax: {
            quietMillis: 150,
            url: '@Url.Action("clientes", "Cliente", new { area = "Comercial" })',
            dataType: 'json',
            data: function (filtro, page) {
                return {
                    pageSize: pageSize,
                    pageNum: page,
                    Filtro: filtro
                };
            },
            results: function (data, page) {
                var more = (page * pageSize) < data.total;
                return {
                    results: data.result,
                    more: more
                };
            }
        },
    }).change(function (e) {
         e.val;
    });
  });

var pageSize = 10;
            $('#Grupo').select2(
            {
                minimumInputLength: 0,
                allowClear: true,
                ajax: {
                    quietMillis: 150,
                    url: '@Url.Action("Grupos", "Cliente", new { area = "Comercial" })',
                    dataType: 'json',
                    data: function (filtro, page) {
                        return {
                            pageSize: pageSize,
                            pageNum: page,
                            Filtro: filtro,
                            ClienteId: ??
                        };
                    },
                    results: function (data, page) {
                        var more = (page * pageSize) < data.total;
                        return {
                            results: data.result,
                            more: more
                        };
                    }
                }
            })