Binding Textbox if dropdown selection matches (in ASP .NET)

Question

a dropdown list and textbox (id =txtSearch) .My db table is book_details. where values are

c_id    book_name   author_name   book_category
1               abc                 ASD            Adventure
2                 def                zxc             Horror
3               ghj                  qwe           Education




in my drop down values are : author,bookname,category.  i want to show the list  in the text box like autocomplete function
if i choose author from drop down then in text box only author names should populate and show the list and if i choose category from dropdown then it musst show the book category list in the drop down


Kindly suggest me in this regard