Radio button checked property data binding

See more:

C#

data-binding

On my form information about a group is displayed as:

1. Group Name:__________ (i/p control: textBox)
2. Is Primary: O No O Yes (i/p control: radioButtons)

I want to data bind the checked property of the two radio buttons above, with my object.
The object is as:

public class DTOItemGroup
    {
        public short id { get; set; }
        public string name { get; set; }
        public Nullable<short> idParent { get; set; }
    }

Back in the code, I tried binding it as:

BindingSource bs;
void InitializeThis(StockTools stockTools)
        {
            bs = new BindingSource();
            bs.DataSource = typeof(DTOItemGroup);
            form_StockTools.tb_GroupName.DataBindings.Add("Text", bs, "name");
            form_StockTools.rb_IsPrimaryNo.DataBindings.Add("Checked", bs, "idParent", true, DataSourceUpdateMode.OnPropertyChanged, false);
            form_StockTools.rb_IsPrimaryYes.DataBindings.Add("Checked", bs, "idParent", true, DataSourceUpdateMode.OnPropertyChanged, true);
        }

Binding for the textbox is working fine. But, for radio buttons, binding is not working at all. Whenever I change the object attached to binding source (bs), the radio buttons doesn't get checked.

I am very new to binding. Please guide me on how to data bind a group of radio buttons.

What I have tried:

I googled for radio button checked property data binding tutorial over google but had no help. I know this must be an easy task, but I can't really figure out it.