Update single row in a WPF DataGrid

Question

I'm creating a download manager, and my WPF DataGrid is bound to a collection of objects representing ongoing downloads (in separate threads). When I have multiple downloads running, each one is using this code to update its DataGrid item every second:

if (DateTime.Now > download.LastUpdateTime.AddSeconds(1))
{
    this.downloadsGrid.Items.Refresh();
    download.LastUpdateTime = DateTime.Now;
}

Datagrid.Items.Refresh() does the job, but it reconstructs the whole DataGrid , causing all downloads to update each others DataGrid rows several times in one second, and I don't want that kind of behavior. Is there any way to refresh a specific row (item) in a DataGrid?

To 'update' single row without refreshing the entire UI https://stackoverflow.com/questions/11324688/how-to-refresh-datagrid-in-wpf/74770140#74770140 — Kamil Pająk, Dec 12 '22 at 11:57

score 9 · Accepted Answer · answered May 08 '12 at 03:08

9

If you bind your DataGrid to an ObservableCollection (which implements INotifyCollectionChanged) your DataGrid will be notified when a new item is added or an item is remove. Additionally, if you're just updating a property on an object in the collection the object should implement INotifyPropertyChanged and raise the PropertyChanged event which will tell the DataGrid to just update that value.

answered May 08 '12 at 03:08

Dan Busha

3,723
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Thank you shriek and Dan Busha. I have a List, but I'm going to switch to ObservableCollection and implement INotifyPropertyChanged on WebDownloadClient by calling PropertyChanged event handler each second to update the datagrid. – marko May 08 '12 at 12:47
What if you want to change the background color depending on the state of the item in observable collection? – Stefan Vasiljevic Sep 13 '14 at 02:24
You'll need to modify the DataRow's style and bind the background value to a Brush property on your row item in the ObservableCollection – Dan Busha Sep 15 '14 at 16:28

score 8 · Answer 2 · answered May 07 '12 at 19:22

8

Does your download class implement INotifyPropertyChanged? If not, that's why you have to call refresh to see a change in the grid. If you implement INotifyPropertyChanged the binding will be updated when the value is changed.

answered May 07 '12 at 19:22

shriek

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Update single row in a WPF DataGrid

2 Answers2

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