Pass the value as a string.
cmdName.selectedItem = "globalName";
use index value to select an item
cmdName.selectedIndex = 2;
index start from 0....
so index of first item will be 0....then 1 for second and so on..
<pre lang="vb">Dim globalName As String = "dfd";
ComboBox1.SelectedItem = globalName</pre>
if globalName is a variable declared by you then.... you should define a default value for that variable which is a item present in your combobox....