Sorting a Collection with dynamic columns using a custom compare function for multiple columns

Question

I need help and ideas on how to sort a ListCollectionView.  My problem is complicated by 3 requirements-
     1. The column values contain HTML tags that needs to be removed before sorting (use custom compareFunction to strip HTML)
     2. The columns are dynamic, so dataField names are not known at compile time (need a single compareFunction for all columns)
     3. The data is used in an AdvancedDataGrid so multi-column sorting is required
I have figured out how to solve any 2 of the 3 requirements.  However, I am having difficulties supporting all 3 requirements.
Any help or ideas would be greatly appreciated.  Thanks.

Answer 1

After playing with this some more I think I've figured out a solution.  This seems to work in initial testing.  Also, there is not a need to capture the current sort column in the headerRelease event which many offered solutions suggested.  Another benefit to this solution is that keyboard initiated sorting is handled also.  Whereas the headerRelease event is only triggered by a mouse click on the column header and special handling is required if the user uses the keyboard to access the column header.
One point that I don't understand is how ascending/decending order is determined.  Behavior seems to be different between a single SortField versus multiple SortFields.  Notice how the compareResults are handled for the different situations.  Anyone out there know why???
 private function colSortCompareFunction(obj1:Object, obj2:Object, fields:Array = null):int{
     var compareResults:int = 0; 
     var newObj1:Object = new Object(); 
     var newObj2:Object = new Object();
      // should not be a condition that is met   
     if (_dataProviderDetails.sort.fields == null)     {
          var s:Sort = new Sort(); 
          var f:Function = s.compareFunction; 
          return f.call(null, obj1, obj2, fields);     }
     // when a single column is selected for sorting   
     else if (_dataProviderDetails.sort.fields.length == 1)     {
          var firstFld:SortField = _dataProviderDetails.sort.fields[0];
          newObj1[firstFld.name] = stripHTML(obj1[firstFld.name]as String);          newObj2[firstFld.name] = stripHTML(obj2[firstFld.name]
as String);
          compareResults = ObjectUtil.compare(newObj1[firstFld.name], newObj2[firstFld.name]);
           return compareResults;     }
     // when multiple columns are selected for sorting   
     else       {
          for each (var fld:SortField in _dataProviderDetails.sort.fields)          {
               newObj1[fld.name] = stripHTML(obj1[fld.name]
as String);               newObj2[fld.name] = stripHTML(obj2[fld.name]
as String);
               compareResults = ObjectUtil.compare(newObj1[fld.name], newObj2[fld.name]);
                if (compareResults != 0)               {
                    if (fld.descending)                    {
                         return compareResults * -1;                    }
                    else                      {
                         return compareResults;                    }
           return compareResults;     }
Does anyone see any problems with this solution?
NOTE:  stripHTML(String) is a simple function using regular expression to remove HTML tags.
Thx