xaml schedule control how to cope with items of vastly differing durations - wpf

Question

I have to create a schedule control using WPF XAML for displaying items with duration as little as 1 seconds and potentially as large as couple of hours.
First thing which seems clear is that I will need some kind of zoom capability, for drilling into the items with very short durations and zooming out to view the items with very large durations.
I have a UI style in mind where by when the control is zoomed to view the large items, any small duration items which generally occur between the large duration items are some how collected in to a 'bucket' which has a height >= a minimum display height. So that I can perhaps hover a mouse over this bucket and get a tool tip which renders the contained items into a time ordered list view.
I am at a loss as to where to begin. I feel that I could perhaps achieve something in the Measure/Arrange overrides of a custom Panel. But I think this could adversely affect render performance. If I were to do it this way, I guess I would need to inject a 'bucket' view into the panels children collection, but that would break the use of ItemTemplate in my Custom Items Control?
My second though is that I create a custom observable collection which has a bindable Scale property which then organises the collection into 'buckets' of a duration large enough to be displayable.
Does anyone have any thoughts on how I should best approach this problem?

Answer 1

I made a similar sounding control which was actually used for inputting employee time shifts. It uses a simple data type in an ObservableCollection data bound to a ListBox.ItemsSource property. I defined a DataTemplate to design the look of each time segment in the UI. It looks like this:
There are certain ComboBoxes along the top which, when changed, change the number of items in the collection. So for example, when the Minutes/segment ComboBox value is changed to Thirty, twice the number of (same sized) items appear in the UI, each now relating to thirty minutes, not sixty. This is done by simply calling a method that repopulates the collection from the relevant property setters. Here is an example:
public TimeSegmentDivision MinutesPerSegment
{
get { return minutesPerSegment; }
set
{
minutesPerSegment = value;
InitializeTimeSegmentsRowViewModels();
NotifyPropertyChanged("MinutesPerSegment");
}
}
private void InitializeTimeSegmentsRowViewModels()
{
if (DayCount == 5) AdjustStartDate(); // (DayCount == 5 is 'Monday - Friday')
DateTime tempDate = Date;
AllTimeSegments = new TimeSegmentsCollection();
for (int m = 0; m < DayCount; m++)
{
TimeSegmentsRowViewModel viewModel = new TimeSegmentsRowViewModel();
viewModel.TimeSegments = InitializeTimeSegments();
AllTimeSegments.Add(viewModel);
date = Date.AddDays(1);
}
NotifyPropertyChanged("AllTimeSegments");
date = tempDate;
}
The specifics of the InitializeTimeSegmentsRowViewModels method is unimportant here, but you should be able to get the right idea from this example.

Answer 2

I worked on custom schedule for Silverlight. It has similar layout loading process so I would try to answer.
I guess your main problem lies in the 'time bar'... Stop thinking about schedule as the big consistent control, it's some pack of custom controls. Take a look on grid. Such controls has a lot peaces.
At start we have to solve first problem - time bar. Right implementation will lead you to painless future))) So time bar it's some control that contains total time, or duration of the employee labors(this value can be set by user). And such thing like step , exactly step and duration will tell you size and position of labors. For time bar control step will tell where are visual ticks should be displayed. I mean time bar will look like rulers, but with time values instead of inches. So we are getting next problem - how to translate time into pixels? Unfortunately I didn't found best solution - I assumed 1min is equal to 1.6 pixels It was perfect for me... But you will have dynamic value that will dynamically increase or decrease pixel length of step. So we have total duration in time, we can convert it into pixels length. But total length could be much bigger then available size. So, now we have another time bar property - visual duration...
okay, I guess you understand my way of thinking... Changing pixel size of step you will get perfect zoom(not step time size, but pixel length).
And yes, you are on the right way if you want create custom panels with overrated measure\arrange methods. And don't worry about item template. It's easiest part. Your parent schedule control will have items source property of object type. All your labors will be content controls....