The MatchItemCount property counts the number of items that matches the current filter criteria. At runtime, the MatchItemCount property is a positive integer if no filter is applied, and negative if a filter is applied. If positive, it indicates the number of items within the control (Count property). If negative, a filter is applied, and the absolute value minus one, indicates the number of matching items after filter is applied. 

The MatchItemCount property returns a value as explained bellow:

• 0, the control displays/contains no items, and no filter is applied to any column
• -1, the control displays no items, and there is a filter applied ( no match found )
• positive number, indicates the number of items within the control (Count property)
• negative number, the absolute value minus 1, indicates the number of items that matches the current filter ( match found )