don't make wxGridTableBase::IsEmptyCell() pure virtual, there is really no point to force all derived table classes to implement it when it has a default implementation which works just fine in 99% of cases

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57047 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/grid.h

@@ -918,7 +918,10 @@ public:
         { return const_cast<wxGridTableBase *>(this)->GetNumberCols(); }
 
 
-    virtual bool IsEmptyCell( int row, int col ) = 0;
+    virtual bool IsEmptyCell( int row, int col )
+    {
+        return GetValue(row, col).empty();
+    }
 
     bool IsEmpty(const wxGridCellCoords& coord)
     {
@@ -1071,7 +1074,6 @@ public:
     int GetNumberCols();
     wxString GetValue( int row, int col );
     void SetValue( int row, int col, const wxString& s );
-    bool IsEmptyCell( int row, int col );
 
     // overridden functions from wxGridTableBase
     //

interface/wx/grid.h

@@ -673,9 +673,14 @@ public:
     //@{
 
     /**
-        Must be overridden to implement testing for empty cells.
+        May be overridden to implement testing for empty cells.
+
+        This method is used by the grid to test if the given cell is not used
+        and so whether a neighbouring cell may overflow into it. By default it
+        only returns true if the value of the given cell, as returned by
+        GetValue(), is empty.
      */
-    virtual bool IsEmptyCell(int row, int col) = 0;
+    virtual bool IsEmptyCell(int row, int col);
 
     /**
         Same as IsEmptyCell() but taking wxGridCellCoords.