so i manage to arrange a solution, if it is the better solution, i dont know, if it works..yes

here goes the code..

@using Infragistics.Web.Mvc
@using System.Collections.Generic
@model IEnumerable<LicenciamentoMVC.Models.Hardware>
@{
ViewBag.Title = "CriarProcesso";
}
<script type="text/javascript">
function GetValOfCompraExterna(row, grid) {
alert(row.CompraExterno);
if (row.CompraExterno == true)
return "Sim";
else
return "Não";
}
function GetValOfCompraExterna2(row2, grid2) {

if (row2.CompraExterno == true)

return "Sim";
else
return "Não";

}
$(function () {

//botao adicionar hardware,abre dialog box para escolher quais os hardwares que quer adicionar
$("#AddHardware").on('click',
function (e) {
$("#igDialog1AddHardware").igDialog("open");
$("#gridHardwareAvailable").igGrid("option", "dataSource", "/Processo/ListarHardware");
$("#gridHardwareAvailable").igGrid("dataBind");
});

$("#AddHardwareToProcesso").on('click',
function (e) {
var rowId;
var ArrayRowSelected= [];

var rows = $("#gridHardwareAvailable").igGridSelection("selectedRows");
$.each(rows, function (ix, row) {
// getting the child grid selected row cell data
rowId = row.element.attr("data-id");
ArrayRowSelected.push(rowId);
});
//mandar o arrays com os ids dos equipamentos
alert("A sua escolha de equipamentos foi gravada com sucesso.")

//fechar a dialog box e fazer o bind da grid hardware do processo
$("#gridHardware").igGrid("option", "dataSource", "/Processo/GravarHardwareSemProcesso?ID="+ArrayRowSelected);
$("#gridHardware").igGrid("dataBind");
$("#igDialog1AddHardware").igDialog("close");
$("#DivGridHardware").show();

});

$("#ControllerButtonOk_CriarProcesso").on('click',
function (e) {
var ArrayRowOnGrid = [];
var idCliente = 0;
//vai buscar id
idCliente = $("#comboClientes").igCombo("value");
// alert(idCliente);
if (!idCliente) {
$("#lblErrosCriarProcesso").text("Tem de escolher um cliente.");
$("#lblErrosCriarProcesso").show();

}
else {

//vai buscar Factura
var NrFactura = $("#editNrFactura").val();
alert(NrFactura);
if (!NrFactura)
NrFactura = "";
//vai buscar a data
var DataFactura = $("#editDataFactura").val();
if (!DataFactura)
DataFactura = "1900/01/01 00:00:00";
//buscar os ids de hardware e guardar os dados
var AllRowsOnGrid = $("#gridHardware").igGrid("allRows");
$(AllRowsOnGrid).each(function (index, row) {

// data key value
IDHardware = $(row).closest('tr').attr("data-id");
alert(IDHardware);
//ArrayRowOnGrid.push(parseInt(IDHardware));
ArrayRowOnGrid.push(IDHardware);

});
alert(ArrayRowOnGrid);
if (ArrayRowOnGrid.length == 0) {
$("#lblErrosCriarProcesso").text("Tem de escolher um ou mais equipamentos.");
$("#lblErrosCriarProcesso").show();
}
else {
//fazer chamada ajax com os valores do formulario
$.ajax({
type: "POST",
url: "/Processo/SaveHardwareSemSoftware",

data: "{'IDCliente':'" + idCliente + "','NrFactura':'" + NrFactura + "','DataFactura':'" + DataFactura + "','IdsHardware':'" + ArrayRowOnGrid + "'}",

contentType: "application/json; charset=utf-8",
dataType: "json",
success: successFunc,
error: errorFunc
});
}
}
function successFunc(data, status) {
if (data == 0)
{
window.location.replace("/Processo/Index");
}
}
function errorFunc() {
alert('Ocurreu um erro inesperado, por favor tente novamente.');
}

});

});
</script>
<h2>Criar Processo</h2>

<table border="1" style="width: 100%;">
<tr style="width: 100%">
<td style="width: 100%" colspan="3">
<input type="button" id="ControllerButtonOk_CriarProcesso" class="button-style" value="OK" />
<input type="button" id="ControllerButtonCancel_CriarProcesso" class="button-style" value="Cancelar" />
</td>
</tr>
<tr style="width: 100%">
<td>
<label id="lblErrosCriarProcesso" style="color: red; display: none;"></label>
</td>
</tr>
<tr style="width: 100%">
<td style="width: 50%">
<label for="txt_Nome">Nome</label>
@(Html.Infragistics().Combo().
ID("comboClientes").
TextKey("Nome").
AutoComplete(false).
FilteringType(ComboFilteringType.Local).
RenderMatchItemsCondition(ComboRenderMatchItemsCondition.StartsWith).
ValueKey("IDCliente").DataSourceUrl(Url.Action("clientes-combo")).
DataBind().
Render())
</td>

<td style="width: 50%">
<div id="dataFactura" style="display: none">
<label for="lblDataCriacao">Data de Criação de Processo</label>
<label for="lblData"></label>
</div>

</td>
</tr>
<tr style="width: 100%">
<td style="width: 50%">
<label for="txt_NrFactura">Número de Factura</label>
<input id="editNrFactura" type="text" aria-labelledby="Nome-ariaLabel" class="required" title="Nr de Factura. This is a required field" />
</td>

<td style="width: 50%">

<label for="lblDataFactura">Data da Factura</label>
<input id="editDataFactura" type="text" aria-labelledby="Nome-ariaLabel" class="required" />

</td>
</tr>
<tr style="width: 100%">
<td style="width: 100%" colspan="3">
<input type="button" id="AddSoftware" class="button-style" value="Adicionar Software" />
<input type="button" id="AddHardware" class="button-style" value="Adicionar Hardware" />
</td>
</tr>
<tr>
<td style="width: 100%" colspan="3">
<div id="GridSoftware" style="display:none">
<h1> Software</h1>
@*aparecer uma grid com para os software adquiridos *@
@( Html.Infragistics().Grid<LicenciamentoMVC.ModelsView.ProcessoCliente>()

.Caption("Software")
.ID("grid1")
.DefaultColumnWidth("200px")
.PrimaryKey("IDLicenca")
.Columns(column =>
{

column.For(x =>x.NomeCliente).DataType("string").HeaderText("Nome Produto").Width("50%");
column.For(x => x.DataInserido).DataType("DateTine").HeaderText("Data de Criação do Processo").Width("25%");
column.For(x => x.NomeCliente).DataType("string").HeaderText("Estado").Width("25%");

column.For(x => x.IDProcesso).DataType("int").Width("0%");




})
.Features(features =>
{
features.Paging().PageSize(20).PrevPageLabelText("Previous").NextPageLabelText("NEXT");
features.Sorting().Mode(SortingMode.Single).ColumnSettings(settings =>
{
settings.ColumnSetting().ColumnKey("NomeCliente").AllowSorting(true);

});
features.Selection().MultipleSelection(false).Mode(SelectionMode.Row);
features.Filtering().Mode(FilterMode.Simple);
features.Updating()
.EnableAddRow(false)
.EnableDeleteRow(true)
.EditMode(GridEditMode.None);

})

.AutofitLastColumn(false)
.Width("100%")
.AutoGenerateColumns(true)
.DataBind()
.Render()
) </div>
</td>
</tr>
<tr>
<td style="width: 100%" colspan="3">
<div id="DivGridHardware" style="display:none" >
<h1> Hardware</h1>
@*aparecer uma grid com para os Hardware adquiridos *@
@( Html.Infragistics().Grid<LicenciamentoMVC.Models.Hardware>()

.Caption("Hardware")
.ID("gridHardware")
.DefaultColumnWidth("200px")
.PrimaryKey("IDHardware")

.Columns(column =>
{


column.For(x =>x.DescricaoHardware).DataType("string").HeaderText("Nome Produto");
column.For(x => x.NumeroSerie).DataType("string").HeaderText("Nr de Série");
column.For(x => x.VersaoFirmware).DataType("string").HeaderText("Versão Firmware");
column.For(x => x.CompraExterno).DataType("string").HeaderText("Compra Externa").Width("0px");

column.For(x => x.IDHardware).DataType("int").Width("0%");
column.Unbound(

"ValCompraExterna").DataType("string").Formula("GetValOfCompraExterna").HeaderText("Comprar Externa");
//formula: function CalculateTotal(data, grid) { return data["UnitPrice"] * data["UnitsInStock"]; }, template: "Total: ${Total}"



})
.Features(features =>
{
features.Paging().PageSize(20).PrevPageLabelText("Previous").NextPageLabelText("NEXT");
features.Sorting().Mode(SortingMode.Single);
features.Selection().MultipleSelection(false).Mode(SelectionMode.Row);
features.Filtering().Mode(FilterMode.Simple);
features.Updating()
.EnableAddRow(false)
.EnableDeleteRow(false)
.EditMode(GridEditMode.None);

})

.AutofitLastColumn(true)

.AutoGenerateColumns(true)

.Render()
)


</div>
</td>
</tr>

</table>

@(Html
.Infragistics()
.Dialog()
.State(DialogState.Closed)
.ContentID("igDialog1AddHardware")
.CloseOnEscape(false)
.HeaderText("Adicionar Hardware")
.ShowCloseButton(false)
.CloseOnEscape(true)
.Width("800px")
.Modal(true)
.Resizable(false)
.Height("600px")

.Render()
)

@* Dialgo box do adicionar *@
<div id="igDialog1AddHardware">

@( Html.Infragistics().Grid<LicenciamentoMVC.Models.Hardware>()

.Caption("Hardware")
.ID("gridHardwareAvailable")
.DefaultColumnWidth("200px")
.PrimaryKey("IDHardware")

.Columns(column =>
{


column.For(x =>x.DescricaoHardware).DataType("string").HeaderText("Nome Produto");
column.For(x => x.NumeroSerie).DataType("string").HeaderText("Nr de Série");
column.For(x => x.VersaoFirmware).DataType("string").HeaderText("Versão Firmware");
column.For(x => x.CompraExterno).DataType("string").HeaderText("Compra Externa").Width("0px");

column.For(x => x.IDHardware).DataType("int").Width("0%");
column.Unbound(

"ValCompraExterna2").Formula("GetValOfCompraExterna2").DataType("string").HeaderText("Comprar Externa");
//formula: function CalculateTotal(data, grid) { return data["UnitPrice"] * data["UnitsInStock"]; }, template: "Total: ${Total}"



})
.Features(features =>
{
features.Paging().PageSize(20).PrevPageLabelText("Previous").NextPageLabelText("NEXT");
features.Sorting().Mode(SortingMode.Single);
features.Selection().MultipleSelection(true).Mode(SelectionMode.Row);
features.Filtering().Mode(FilterMode.Simple);
features.Updating()
.EnableAddRow(false)
.EnableDeleteRow(false)
.EditMode(GridEditMode.None);

})

.AutofitLastColumn(true)
.Width("100%")
.Height("500px")
.AutoGenerateColumns(true)

.Render()
)
<input type="button" id="AddHardwareToProcesso" class="button-style" value="Adicionar Hardware" />
</div>

the solution is to bind the data to the grid on a button click instead on binding it when the page start..

$("#AddHardware").on('click',
function (e) {
$("#igDialog1AddHardware").igDialog("open");
$("#gridHardwareAvailable").igGrid("option", "dataSource", "/Processo/ListarHardware");
$("#gridHardwareAvailable").igGrid("dataBind");
});

Thanks