OverheadSheetInfo.Columns Property

try
 {
     // Get the overhead workbook. The lock is required.
     es.CurrentVersion.Overhead.GetLockOnWorkbook();
     var wsMgr = es.CurrentVersion.Overhead.WorksheetManager;
     var wbook = es.CurrentVersion.Overhead.GetWorkbook();
 
     foreach (IWorksheet sheet in wbook.Worksheets)
     {
         // Find the sheet for the "LIST1" field, which is of type "List (Name only)".
         // The "LIST1" is the mnemonic, not the name, which may be localized. The OverheadSheetInfo.Name contains the mnemonic,
         // and the OverheadSheetInfo.LocalizedName contains the latter.
         var sheetInfo = wsMgr.GetOverheadSheetInformation(sheet);
         if (sheetInfo.Type == NativeSheetType.List_Box && sheetInfo.Name == "LIST1")
         {
             // Get only the columns that were added by the user. Exclude the non-removable native columns.
             var userColumns = sheetInfo.Columns.Where((col) => col.Kind != OverheadSheetColumnKind.NativeColumn);
 
             // Sort them by the position.
             var sortedUserColumns = userColumns.OrderBy((col) => col.Position);
 
             // Display their headers.
             string s = "";
             foreach (var column in sortedUserColumns)
             {
                 s += column.Header1 + " | " + column.Header2 + " | " + column.Header3 + " | " + "\n";
             }
             MessageBox.Show(s);
         }
     }
 }
 catch (Exception generalError)
 {
     // Catches all errors to get the proper message.
     MessageBox.Show(generalError.Message, "Error!", MessageBoxButtons.OK, MessageBoxIcon.Error);
 }
 finally
 {
     // Release the lock on the overhead workbook in any case.
     es.CurrentVersion.Overhead.ReleaseLockOnWorkbook();
 }