Multi select DropDownList in ASP.NET

I needed a dropdown list that allows multi select, a sort of checkbox list paired with a dropdown. For example is very useful when working with months. MS Reporting Services has one.

After googling for a while, I couldn’t find one to satisfy me and I started to play with a dropdown. A click on dropdown and a list of checkboxes appears, another click and the list dissappears. Problem was that the dropdown wanted to show it’s “Select month” option.

Long story short, I paired a TextBox, styled with css to have a “select arrow”, with a CheckBoxList and some jQuery:

Multiselect DropDownList

And here is the code: MonthsControl-src.7z