Question

I am attempting to store metadata in my ComboBox elements by overriding a Dictionary<>’s ToString(). However, my ToString() override does not appear to be executing, and I can’t figure out why. The ComboBox displays “(Collection)” instead of the value I specify. Is there a step I’m missing to get the ComboBox to use my ToString() override?

public class ComboElement : Dictionary<string,object> {
  protected string defaultkey = "";
  public ComboElement( SqlDataReader sdr, string defkey )
    : base() {
    defaultkey = defkey;
    for ( int field = 0; field < sdr.FieldCount; field++ ) {
      this.Add( sdr.GetName( field ), sdr[field] );
    }
  }
  public override string ToString() {
    return "GLURP"; //
    //if ( this.ContainsKey( this.defaultkey ) == true ) { return this[this.defaultkey].ToString(); } else return "";
  }
}

Code to populate ComboBox on DropDown:

      while ( sdr.Read() == true ) {
        ComboElement ce = new ComboElement( sdr, "filename" );
        string tstring = ce.ToString(); // Correct value
        cmbFiles.Items.Add( ce ); // Displays "(Collection)"
      }

Answer 1

I would try adding a DisplayValue property to your ComboElement class and then setting the DisplayMember of the ComboBox to the name of this property.