How to display index number and text value in the listbox asp.net c#

I want to display index value along with the text value of the listbox. If we are moving the item up and down the index value remains the same. only the text hast to cha开发者_如何转开发nge.

Code i am using to move the item up and down:

         <script type="text/javascript" language="Javascript">
       function MoveUp() {
           var con = document.getElementById("lbRank");
           if (con.selectedIndex >= 0) {
               for (var count = 1; count < con.options.length; count++) {
                   if (con.options[count].selected == true) {
                       var tem = con.options[count].text;
                       con.options[count].text = con.options[count - 1].text;
                       if (con.options[count - 1].selected == false) {
                           con.options[count].selected = false;
                       }
                       con.options[count - 1].selected = true;
                       con.options[count - 1].text = tem;
                   }
               }
           }
           else {
               alert('Select any item');
           }

       }

       function MoveDown() {
           var con = document.getElementById("lbRank");
           if (con.selectedIndex >= 0) {
               for (var count = con.options.length - 2; count >= 0; count--) {
                   if (con.options[count].selected == true) {
                       var tem = con.options[count].text;
                       con.options[count].text = con.options[count + 1].text;
                       if (con.options[count + 1].selected == false) {
                           con.options[count].selected = false;
                       }
                       con.options[count + 1].selected = true;
                       con.options[count + 1].text = tem;
                   }
               }
           }
           else {
               alert('Select any item');
           }
       }
</script>