c# - DropDownListItems. Can't set any items to be disabled when bound to a datasource -

i'm using code below grab list of items database , bind them dropdownlist.

i insert separator lines in itemlist , set

seperator.attributes.add("disabled", "true"); seperator.enabled = false; 

this should make items non-selectable in dropdown doesn't.

if loop through items after i've bound them, work. surely should able disable items before bind them dropdownlist?

dropdownlist gvcategory = (dropdownlist)gridviewactvities.rows[0].findcontrol("gvcategory"); gvcategory.datasource = formatcategorieslistitems(); gvcategory.databind();  public listitemcollection formatcategorieslistitems() {     oracleconnection sqlconn = new oracleconnection(configurationmanager.connectionstrings["connectionstring1"].connectionstring);     sqlconn.open();     oraclecommand sqlselect = new oraclecommand(@"select id, taskgroup, taskcategory hott_groups_cats order 'sort'", sqlconn);     sqlselect.commandtype = system.data.commandtype.text;     oracledataadapter sqladapter = new oracledataadapter(sqlselect);     dataset mydataset = new dataset();     sqladapter.fill(mydataset);     sqlconn.close();      listitemcollection listitems = new listitemcollection();     //add blank item     listitems.add(new listitem(""));     string previoustaskgroup = "";     // database items list ready bind dropdown     (int = 0; < mydataset.tables[0].rows.count; i++)     {         string taskgroup= mydataset.tables[0].rows[i]["taskgroup"].tostring();         string taskcategory = mydataset.tables[0].rows[i]["taskcategory"].tostring();         string taskid= mydataset.tables[0].rows[i]["id"].tostring();         // insert seperator row based on taskgroup         if (taskgroup != previoustaskgroup)         {             listitem seperator = new listitem("--" + taskgroup + "--", "");             seperator.attributes.add("disabled", "true");             seperator.enabled = false;             listitems.add(seperator);             if (i != mydataset.tables[0].rows.count)             {                 previoustaskgroup = mydataset.tables[0].rows[i]["taskgroup"].tostring();                 i--;             }         }         else         {             listitems.add(new listitem(" " + taskcategory, taskid));             if (i != mydataset.tables[0].rows.count)             {                 previoustaskgroup = mydataset.tables[0].rows[i]["taskgroup"].tostring();             }         }     }      return listitems; } 

unfortunately case, don't think possible before bind that. here question on subject: make drop down list item unselectable

update:

i'm editing answer based on derrick's answer , comment it. derrick suggesting after dropdownlist bound, go through , disable separators. more this:

protected void gvcategory_databound(object sender, eventargs e) {     foreach (listitem li in gvcategory.items)     {         if(li.text.contains("--"))             li.attributes.add("disabled", "true");     } } 

update 2:

add ondatabound event manipulate dropdownlist after bound.

<asp:dropdownlist id="gvcategory" runat="server" ondatabound="gvcategory_databound"></asp:dropdownlist>