In my .xaml file I have my combo box as below:
You can do it like following
private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var comboBoxItem = e.AddedItems[0] as ComboBoxItem;
if (comboBoxItem == null) return;
var content = comboBoxItem.Content as string;
if (content != null && content.Equals("some text"))
{
//do what ever you want
}
}