protected FrameworkElement PrepareGroupHeader(GroupHeaderItem headerItem, FrameworkElement lvParent)
{
var result = new ListViewGroupHeader()
{
Context = headerItem,
Content = headerItem,
Screen = _parent.Screen,
VisualParent = lvParent,
LogicalParent = lvParent
};
// Set this after the other properties have been initialized to avoid duplicate work
// No need to set the LogicalParent because styles and content templates don't bind bindings
result.Style = MpfCopyManager.DeepCopyCutLVPs(GroupHeaderContainerStyle);
result.ContentTemplate = MpfCopyManager.DeepCopyCutLVPs(GroupHeaderTemplate);
return(result);
}
private FrameworkElement GetOrCreateGroupHeader(int itemIndex, HeaderItemWrapper headerWrapper, FrameworkElement lvParent, out bool newCreated)
{
if (headerWrapper.HeaderItem != null)
{
newCreated = false;
return(headerWrapper.HeaderItem);
}
var headerItem = new GroupHeaderItem()
{
FirstItem = _items[itemIndex],
GroupingValue = headerWrapper.GroupingValue
};
newCreated = true;
var result = PrepareGroupHeader(headerItem, lvParent);
headerItem.LogicalParent = result;
headerWrapper.HeaderItem = result;
return(result);
}
private HeaderItemWrapper GetGroupHeader(int itemIndex)
{
var headerWrapper = _materializedGroupHeaders[itemIndex];
if (headerWrapper != null)
{
return(headerWrapper);
}
if (_groupingValueProvider != null)
{
headerWrapper = new HeaderItemWrapper(_groupingValueProvider.GetGroupingValue(_items[itemIndex]));
}
else
{
// to get the grouping value of the item we use a dummy header item and apply the DataContext and group value binding to it
if (_getValueGroupHeader == null)
{
_getValueGroupHeader = new GroupHeaderItem();
var dd = new SimplePropertyDataDescriptor(_getValueGroupHeader, typeof(GroupHeaderItem).GetProperty("GroupingValue"));
var binding = MpfCopyManager.DeepCopyCutLVPs(_groupPropertyBinding);
binding.SetTargetDataDescriptor(dd);
binding.Activate();
}
_getValueGroupHeader.DataContext = new BindingExtension()
{
Source = _items[itemIndex],
Path = "."
};
// then we create the actual header item and apply the value to it
headerWrapper = new HeaderItemWrapper(_getValueGroupHeader.GroupingValue);
// finally cleanup the datacontext binding
MPF.TryCleanupAndDispose(_getValueGroupHeader.DataContext);
_getValueGroupHeader.DataContext = null;
}
_materializedGroupHeaders[itemIndex] = headerWrapper;
return(headerWrapper);
}