Wpf listview itemssource not updating

27-May-2017 20:45

Not necessary the healthiest design, but the performance is quite a bit better.Using implicit Control Template/Data Template styles will also help keep your code and XAML organized without the need for either . Behavior On Detaching signals the removal of a behavior from a control (generally never, as behaviors don’t get removed from controls).It keeps the observed object (generally, your view model) from accidentally holding a strong reference to your view. Viewmodels tend to have a longer lifetime than views (consider a virtualized Items Control), so it’s possible that your view model will inadvertently gather references to views.If your views or behaviors rely on events being raised from a viewmodel (as innocuous as INotify Property Changed. Use classes like Property Changed Event Manager or Collection Changed Event Manager, or (painfully) use the Weak Event Manager to create your own event manager for your custom events.This may not always be a practical or desirable solution, but layout passes perform faster when widths and heights do not have to be recalculated.They may also help stop a layout pass from rippling through an entire visual tree.For views, you get the get a WPF notification that a viewmodel is about to go unused by a view.

Again, Items Controls will usually exacerbate performance problems with deep visual trees because if they’re not being virtualized, they’re being destroyed and recreated; if they are being virtualized, changing Data Context in a deeper tree takes more time than changing Data Context in a shallower one. The Unloaded event is a better place for that, but be aware that it will get raised every time the control is removed from the visual tree. Add Value Changed classes cause the WPF framework to take a strong reference to the source of the event that isn’t removed until you call Dependency Property Descriptor. This class is frequently used in conjunction with Behaviors, so if you have Remove Value Changed in On Detaching, you’re likely leaking memory.

There is no shortage of information out there on how to speed up the performance of WPF applications, but too often the focus is on the weird stuff instead of the simpler issues.

I’m not going to talk about things like writing to to optimize drawing—it’s a topic covered to death elsewhere.

And always set specific widths on columns in a grid (be it a List View Grid View or any third-party control), because these tend to be very expensive, especially with larger data sets.

Grouping in WPF doesn’t perform terribly well, especially with List Views and Grid Views.

Again, Items Controls will usually exacerbate performance problems with deep visual trees because if they’re not being virtualized, they’re being destroyed and recreated; if they are being virtualized, changing Data Context in a deeper tree takes more time than changing Data Context in a shallower one. The Unloaded event is a better place for that, but be aware that it will get raised every time the control is removed from the visual tree. Add Value Changed classes cause the WPF framework to take a strong reference to the source of the event that isn’t removed until you call Dependency Property Descriptor. This class is frequently used in conjunction with Behaviors, so if you have Remove Value Changed in On Detaching, you’re likely leaking memory.

There is no shortage of information out there on how to speed up the performance of WPF applications, but too often the focus is on the weird stuff instead of the simpler issues.

I’m not going to talk about things like writing to to optimize drawing—it’s a topic covered to death elsewhere.

And always set specific widths on columns in a grid (be it a List View Grid View or any third-party control), because these tend to be very expensive, especially with larger data sets.

Grouping in WPF doesn’t perform terribly well, especially with List Views and Grid Views.

For example, if you have a Person View Model class with a property that you want to group by (let’s say Region), it is faster to create a mixed collection of My Group View Model and Person View Model objects, ordered correctly by group, with different Data Templates, than it is to bind to a grouped collection. And worse, once you start nesting Dynamic Resources (for example, a List View whose Style contains a Control Template that references objects through Dynamic Resources), you’re likely to run into situations where you leak controls.