When wxPGProperty is un-attached from wxPropertyGrid, keep its 'default' cell references invalid/NULL (fixes #12552)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65788 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/propgrid/property.h

@@ -306,6 +306,13 @@ public:
         return *this;
     }
 
+    // Used mostly internally to figure out if this cell is supposed
+    // to have default values when attached to a grid.
+    bool IsInvalid() const
+    {
+        return ( m_refData == NULL );
+    }
+
 private:
     virtual wxObjectRefData *CreateRefData() const
         { return new wxPGCellData(); }
@@ -2395,6 +2402,11 @@ protected:
 
     void ClearFlag( FlagType flag ) { m_flags &= ~(flag); }
 
+    // Called when the property is being removed from the grid and/or
+    // page state (but *not* when it is also deleted).
+    void OnDetached(wxPropertyGridPageState* state,
+                    wxPropertyGrid* propgrid);
+
     // Call after fixed sub-properties added/removed after creation.
     // if oldSelInd >= 0 and < new max items, then selection is
     // moved to it.

samples/propgrid/tests.cpp

@@ -1030,13 +1030,17 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
         wxPGProperty* p;
 
         wxPGProperty* origParent =
-            pgman->GetProperty(wxT("Window Styles"))->GetParent();
+            pgman->GetProperty("Window Styles")->GetParent();
 
-        p = pgman->RemoveProperty(wxT("Window Styles"));
+        // For testing purposes, let's set some custom cell colours
+        p = pgman->GetProperty("Window Styles");
+        p->SetCell(2, wxPGCell("style"));
+        p = pgman->RemoveProperty("Window Styles");
         pgman->Refresh();
         pgman->Update();
 
         pgman->AppendIn(origParent, p);
+        wxASSERT( p->GetCell(2).GetText() == "style");
         pgman->Refresh();
         pgman->Update();
     }

src/propgrid/property.cpp

@@ -499,6 +499,23 @@ void wxPGProperty::InitAfterAdded( wxPropertyGridPageState* pageState,
     wxPGProperty* parent = m_parent;
     bool parentIsRoot = parent->IsKindOf(CLASSINFO(wxPGRootProperty));
 
+    //
+    // Convert invalid cells to default ones in this grid
+    for ( unsigned int i=0; i<m_cells.size(); i++ )
+    {
+        wxPGCell& cell = m_cells[i];
+        if ( cell.IsInvalid() )
+        {
+            const wxPGCell& propDefCell = propgrid->GetPropertyDefaultCell();
+            const wxPGCell& catDefCell = propgrid->GetCategoryDefaultCell();
+
+            if ( !HasFlag(wxPG_PROP_CATEGORY) )
+                cell = propDefCell;
+            else
+                cell = catDefCell;
+        }
+    }
+
     m_parentState = pageState;
 
 #if wxPG_COMPATIBILITY_1_4
@@ -621,6 +638,27 @@ void wxPGProperty::InitAfterAdded( wxPropertyGridPageState* pageState,
     }
 }
 
+void wxPGProperty::OnDetached(wxPropertyGridPageState* WXUNUSED(state),
+                              wxPropertyGrid* propgrid)
+{
+    if ( propgrid )
+    {
+        const wxPGCell& propDefCell = propgrid->GetPropertyDefaultCell();
+        const wxPGCell& catDefCell = propgrid->GetCategoryDefaultCell();
+
+        // Make default cells invalid
+        for ( unsigned int i=0; i<m_cells.size(); i++ )
+        {
+            wxPGCell& cell = m_cells[i];
+            if ( cell.IsSameAs(propDefCell) ||
+                 cell.IsSameAs(catDefCell) )
+            {
+                cell.UnRef();
+            }
+        }
+    }
+}
+
 wxPGProperty::wxPGProperty()
     : wxObject()
 {
@@ -1525,6 +1563,8 @@ void wxPGProperty::EnsureCells( unsigned int column )
         wxPropertyGrid* pg = GetGrid();
         wxPGCell defaultCell;
 
+        if ( pg )
+        {
             // Work around possible VC6 bug by using intermediate variables
             const wxPGCell& propDefCell = pg->GetPropertyDefaultCell();
             const wxPGCell& catDefCell = pg->GetCategoryDefaultCell();
@@ -1533,6 +1573,7 @@ void wxPGProperty::EnsureCells( unsigned int column )
                 defaultCell = propDefCell;
             else
                 defaultCell = catDefCell;
+        }
 
         // TODO: Replace with resize() call
         unsigned int cellCountMax = column+1;

src/propgrid/propgridpagestate.cpp

@@ -1934,6 +1934,8 @@ void wxPropertyGridPageState::DoDelete( wxPGProperty* item, bool doDelete )
     // We can actually delete it now
     if ( doDelete )
         delete item;
+    else
+        item->OnDetached(this, pg);
 
     m_itemsAdded = 1; // Not a logical assignment (but required nonetheless).