I have a dropdownlist, which dynamically populate data from SQL Server and i wanna manually insert two items on top of the DDL after data binding. So, the DDL would has data something like this:

Select Branch (manually insert)
ALL (manually insert)
AIR
AMP
ABG
...

I tried to achieve it by using code below:

ddlBranch.Items.Insert(0, "Select Branch")
ddlBranch.Items(0).Value = CMM.sExcVal1

ddlBranch.Items.Insert(1, "ALL")
ddlBranch.Items(1).Value = "ALL" 

but it comes out giving me the data like this:

Select Branch (manually insert)
ALL (manually insert)
('AIR' branch should be here but it's gone)
AMP
ABG
...

After manually insert the 'ALL' item into the DDL, the 'AIR' is gone which is already replaced by the 'ALL'. How can i remain all the data from server and at the same time i can manually insert two items?