Q:

C# Combobox Selection

I am populating a combobox dropdown with node fields from an Xml document.  I have that working.  Now I have the text in the dropdown menu of the combobox.  I want to be able to press a 'Go' button and use the selected text.  What are the commands please? 

A:

Have a look at the SelectedText property of ComboBox.  It will return a string containing the currently selected text (ie.  the text of the currently selected item) of the combo box. 
To handle this from a button press, add an OnClick event handler to the button, and in this event handler get the SelectedText and do what you need with it.