Wpf itemssource binding not updating

16-Jun-2016 11:45 by 2 Comments

Wpf itemssource binding not updating - Free live typing sex chat

Just letting the ‘arrow down’ key makes the UI freeze too much for me.With the delay property set to a value of 500 milliseconds, I can easily navigate in the list with the keyboard.

The third List View of the simple application uses this approach; the XAML looks like this: [Click here to download the sample application demonstrating everything described here.] What's neat is how something that started out as a minor annoyance turned into a great learning opportunity!I was working on a WPF project the other day and wanted an easy way to display data in a simple tabular format: a few columns (with headers) that would automatically size to fit their contents.The obvious choice was the List View control and its Grid View View which do exactly this.This synchronisation is done immediately : each change of the target value, even a tiny tiny one update the source.Since WPF 4.5, the Binding has a new property named ‘Delay’ which defines a timespan after which the source is updated. As this is an added property on the Binding, you only have to define it on each Binding you create.(If you're not familiar with attached behaviors, you can read more about them in this post by John Gossman or this article by Josh Smith.) In the case of the attached behavior solution to this problem, we make use of the Dependency Property Descriptor class to attach a change handler to the Items Source property of the List View - and then call the method above to actually update the widths of the columns.

There end up being a few more lines of code with this solution because of what it takes to create an attached Dependency Property and attach/remove a handler for it, but that code is completely self-contained and can live entirely in its own dedicated class (whereas the method used by the previous solution needs to be part of one of the application's classes).

:) Okay, so if you're still reading, then your scenario is probably like mine: changes to the data source can occur without the application explicitly knowing about it.

That last bit may not make a lot of sense until you realize that it's possible to implement a great deal of an application's functionality entirely in XAML.

Each update of the target value will be done only after this delay and only if none has been done since. The delay is defined in milliseconds and the default value of ‘0’ reproduce the classic behavior of a Binding.

Here is an example of a binding which sets a delay of 500 milliseconds: The master/detail scenarii are the one where it can be the most useful for me so I have create a demo project to reproduce it.

A Binding performs synchronisation between two properties.

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