Adding Line To Asp.net To Listbox

I need a line added to a listbox in ASP.NET to provide some separation from the many options the user can choose from. Currently, we have over 20 different options for the user to

Solution 1:

You can use the optgroup tag to give separation.

<select><optionvalue="XX"/><optgrouplabel="separation"/><optionvalue="BB"/></select>

To give only a line you will need to do some trickery. See below

<styletype="text/css">
    optgroup {border-bottom:solid thin black; width:100%;}
</style><select><optionvalue="XX"/><optgrouplabel=" "/><optionvalue="BB"/></select>

If your data is already loaded you could run some jquery after.

$('select option[value="XX"]').after('<optgroup label=""/>');

Solution 2:

There is no out-of-the box possibility to create option-groups from DropDownLists nor Listboxes in asp.net.

Found those articles providing a server-side and client-side solution to achieve what you are looking for:

Optgroup in .NET Listbox

Dropdownlist control with <optgroup>s for asp.net (webforms)?