I am populating a comboBox from a database through the use of its propery - `Use Data Bound Items`  

Instead of making another table, I just added another 2 Columns in MainTable.  

they should be `DVRID` and `DVRIP`  

then I populated my `comboDVR` from `DVRID` and I get `DVR16F` & `DVR14F` on my dropdown and their `selectedValues` are from `DVRIP` which is their own ip addresses.  

I typically get what I want, only problem is, since I populated my `comboDVR` from a column, it gets all items in that column even the null ones..
![enter image description here](https://i.stack.imgur.com/44fVr.jpg)
so when I dropdown, its too long.. and if a user click on a blank item, throws and exception.  

is there a way that I can remove or not get null values from DRVID column? or do I need to create a separate table for that? 

**btw** I do this because my boss said he does not want the client to manually input the dvr's ip address so he wants a dropdown menu of the dvrs' names instead.