wpf render gui async - wpf

Question

i got an ItemsControl with an Expander in it and in the Expander are a view ProgressBars inclued. My problem is when i am loading the data (which is not my performance problem) and then i update PropertyChanged of my ItemSource my gui freezes for a long time cuz it needs so long to render.
Is there a way i can redner the gui elements async so that my gui doesnt freeze???
I already searched a bit, though im not sure if my search results solve my problem.
So i am asking here, hoping for a nice solution.
They gui does look something like this.. though there are usually more elements
you all can imageine the xaml code behind...
private void RefreshOverview(){
...
foreach (Characteristic c in characteristics)
{
Area a = c.Area;
Characteristic c1 = c;
foreach (Line l in lines.Where(l => l.Product.Id == c1.Product.Id))
{
List<IMeasurementSchedule> measurementSchedules;
// take DefaultMeasurementSchedules if exists
if (c.DefaultMeasurementSchedules == null || c.DefaultMeasurementSchedules.Count == 0)
measurementSchedules = new List<IMeasurementSchedule>(l.LineMeasurementSchedules.ToArray());
else
measurementSchedules = new List<IMeasurementSchedule>(c.DefaultMeasurementSchedules.ToArray());
foreach (IMeasurementSchedule ms in measurementSchedules)
{
MeasureCharacteristic mc;
if (a.PeripheryEnabled)
{
Line l1 = l;
foreach (AreaItem ai in areaitems.Where(x => x.AreaId == a.Id && x.LineId == l1.Id))
{
mc = (from cm in _context.CharacteristicMeasures.Local
where cm.Charge == null &&
cm.Characteristic.Id == c.Id &&
cm.Line.Id == l.Id &&
cm.ShiftIndex.Id == actualShiftIndex.Id &&
cm.AreaItem != null &&
cm.AreaItem.Id == ai.Id &&
cm.MeasureScheduleId == ms.Id
select cm).FirstOrDefault() ??
new MeasureCharacteristic
{
Characteristic = c,
Line = l,
ShiftIndex = actualShiftIndex,
AreaItem = ai
};
mc.MeasureSchedule = ms;
characteristicsMeasures.Add(AddMeasures(mc));
}
}
else
{
mc = (from cm in _context.CharacteristicMeasures.Local
where cm.Charge == null &&
cm.Characteristic.Id == c.Id &&
cm.Line.Id == l.Id &&
cm.ShiftIndex.Id == actualShiftIndex.Id &&
cm.MeasureScheduleId == ms.Id
select cm).FirstOrDefault() ??
new MeasureCharacteristic {Characteristic = c, Line = l, ShiftIndex = actualShiftIndex};
mc.MeasureSchedule = ms;
characteristicsMeasures.Add(AddMeasures(mc));
}
}
}
}
MeasureCharacteristics = characteristicsMeasures;
MeasureCharacteristicsByType =
CharacteristicMeasureGroupedByType.GetExpanderViewProductItems(characteristicsMeasures);
}
thats my code ;) MeasureCharacteristicsByType is a IEnumerable<CharacteristicMeasureGroupedByType> i do bind my itemsource to. if you need more information just ask!!!
UPDATE
here is my link to my xaml code..
http://pastebin.com/UA777LjW

Answer 1

You are mixing logic to build your data and rendering operations.
Isolate the one from the other to identify which is taking time.
For example don't affect MeasureCharacteristicsByType in the same for loop as the linq queries.
Then measure times with a StopWatch instance.
If the rendering takes the most time, insert the items in the MeasureCharacteristicsByType one by one (not at the same time), with this kind of instruction to render them one after the other :
foreach(var charMeasureByType in CharacteristicMeasureGroupedByType.GetExpanderViewProductItems(characteristicsMeasures))
{
Dispatcher.BeginInvoke(new Action<OneTypeHere>((OneTypeHere item) =>
{
MeasureCharacteristicsByType.Add(item)
}), DispatcherPriority.Background, charMeasureByType);
}
Edit : OneTypeHere is the type of charMeasureByType.