for (int i = 0; i < myGrid.Items.Count; i++)
{
var item = myGrid.Items[i];
var mycheckbox = myGrid.Columns[5].GetCellContent(item) as CheckBox;
if ((bool)mycheckbox.IsChecked)
{
string ID = (myGrid.SelectedCells[1].Column.GetCellContent(item) as TextBlock).Text;
}
Massege.Show(ID);
}