c# - Set ComboBox Text on Basis of SelectedIndex -

i trying set text property of combobox on basis of selectedindex problem text becoming string.empty after changing index of combobox.

each item in combobox correspond string in datatable having 2 columns name, description

what need when users select's name (index changes) when want show description of in combobox

what have tried :

private void tbtag_selectionchangecommitted(object sender, eventargs e) {     // data selected index     tagrecord tag = tbtag.selecteditem tagrecord;      // after getting data reset index     tbtag.selectedindex = -1;      // after resetting index, change text     tbtag.text = tag.tagdata; } 

how have populated combobox

//load tag list datatable tags = tagmanager.tags;  foreach (datarow row in tags.rows) {     tagrecord tag = new tagrecord((string)row["name"], (string)row["tag"]);     tbtag.items.add(tag); } 

helper class used :

private class tagrecord {     public tagrecord(string tagname, string tagdata)     {         this.tagname = tagname;         this.tagdata = tagdata;     }      public string tagname { get; set; }     public string tagdata { get; set; }      public override string tostring()     {         return tagname;     } } 

i think happens because -1 index in combobox means no item selected (msdn) , trying change text of it. create 1 more element (at index 0) , make change text depending on selection:

bool newtagcreated = false;  private void tbtag_selectionchangecommitted(object sender, eventargs e) {      tagrecord tag = tbtag.selecteditem tagrecord;     tagrecord newtag = null;      if (!newtagcreated)     {       newtag = new tagrecord(tag.tagdata, tag.tagname); //here change going displayed        tbtag.items.insert(0, newtag);       newtagcreated = true;     }     else     {       newtag = tbtag.items[0] tagrecord;       newtag.tagname = tag.tagdata;     }      tbtag.selectedindex = 0; }