Fetch list items and fill DropdownList control?

I have a list: Name- ProjectList

ProjectList:

Titile(Text)                                                           AssignTo(Person or Group)

Project-1                                                                 John

Project-2                                                                 Steve

Project-3                                                                  John

Project-4                                                                 Steve

I have a Dropdownlist control:

Button_Click:

If I am site collection administrator and I click this button then Dropdownlist control

Should be fill with all items dynamically like:

Dropdown contorol:

Project-1                                                                 

Project-2                                                                 

Project-3                                                                 

Project-4     

If I am user “john” and click this button then     Dropdownlist control

Should be fill with with related itrms dynamically like:

  Dropdown contorol:

Project-1                                                                

Project-3                                                                 

If Steve then

        Dropdown contorol:

Project-2                                                                

Project-4

Thanks,

Vishwa