Updating Timeline

[Amige]

 Hello,

In my application I need to update the ItemsSource every few seconds, I would like to know what would be the best way to perform this.

I might have up to 600 items divides

I have an ObervableCollection object, every time I receive new data I clear the ObervableCollection object and then I add the new data, something like this:
 

ObservableCollection<myData> myCollection = new ObservableCollection<myData>();

// Format the data the way I need it

myCollection.Clear();

foreach (myObject item in DataObject)
{
  myCollection.Add(new myData()
    {
        property1 = item.property1,
        property2 = item.property2,
        property3 = item.property3
        // Operations for other properties
​

    });
}

I wonder if it would be better to update my ObervableCollection object (update existing items, add the new ones, and delete those that no longer exist) than clear and add all again.

What I want to achieve is to reduce the rendering time.

I hope you can give me some advice.

Thanks in advance,

Alberto

 

 

 

[Petar Marchev]

Hi Amige,

When the items source changes in any way, the whole timeline is redrawn. This is due to various reasons, such as if the timeline uses grouping and an item changes - the number of groups or order of groups may change. So all previous items are released and new ones are created.

With this being said, we think that you will get the same performance in all cases. However, if you need to you can try both approaches and see if you detect any difference in the performance. Let us know if you need more information.

Regards,
Petar Marchev
Telerik

 

 

[Amige]

Hello Petar,

Thanks for claryfing me the way the timeline is redrawn.

I'll try the second approach and see if the performance improves a little.

Regards,

Alberto

[Leland]

I am experiencing a significant performance hit to the application when I update the timeline every 2 seconds. I'm adding 2 items and removing 2 items from the ObservableCollection every 2 seconds at event end. The previous items are changing slightly in size as new items are added, which suggests that the entire view may be re-rendered. Can you confirm this to be the case?

[Martin Ivanov]

Hello Leland,

Yes, changes in the ItemsSource of the control trigger redrawing of the items. I've tested the described scenario but the I wasn't able to notice a significant performance hit in my project. Can you check it out and let me know if I am missing anything?

Regards,
Martin Ivanov
Progress Telerik