LINQ Combobox Databinding behave weird - linq

Question

I'm having a WinForm on witch I've a DataGridView that display a list of sites. bellow that grid i've a TextBox and a Combobox, using DataBinding the textbox show the current value "Code" grid column and the combobox show the province. The combobox is filled with a list for province
The weird thing is this:
When I change the combobox selected province for another one, at the time when the focus leave the combobox, the original value of the of the combobox return. I can't find a way for the combobox to keep the changed value.
what am I doing wrong?
Here my the code of my workbench project;
private void Form1_Load(object sender, EventArgs e)
{
context = new GMR_DEVEntities();
lSite = from t in context.tblSites where t.Actif == true select t;
this.dataGridView1.DataSource = lSite;
this.dataGridView1.AutoGenerateColumns = true;
Guid ProvinceId = Guid.Parse("00000000-0001-0000-0008-000000000001");
IQueryable<tblDomVal> provinces = from prov in context.tblDomVals where prov.pTypeDomValID == ProvinceId select prov;
comboBox1.DataSource = provinces;
comboBox1.ValueMember = "ID";
comboBox1.DisplayMember = "DescrFr";
textBox1.DataBindings.Add(new Binding("Text", lSite, "Code"));
comboBox1.DataBindings.Add(new Binding("SelectedValue", lSite, "pProvinceID", false, DataSourceUpdateMode.OnPropertyChanged));
}
Any help would be welcome :)
Hugo

Answer 1

Try creating a new binding context for you combo
BindingContext oBC = new BindingContext();
comboBox1.BindingContext = oBC;
comboBox1.DataBindings.Add(new Binding("SelectedValue", lSite, "pProvinceID", false, DataSourceUpdateMode.OnPropertyChanged));

Answer 2

While searching for a solution, I've discover that the problem have something to do with the Datatype (All my tables IDs are GUID), I've change the Binding to bind with a varchar field instead of the guid, and thing went good. So the problem have something to do with GUID. But I'll change my approach, and work with manual bind