I am having a collection bound to a WPF ListBox, I want to make the listboxItems aprear one after the other one first binding to the data. To have an effect similar to powerPoint one.
Two options spring to mind:
A. create a storyboard that animates opacity, and apply it to the ItemTemplate
B. use a timer on a background thread to add items one-by-one to the bound collection
Couldn't you just use a timer and add the items to the collection one by one, raising a property changed event in between?
Related
I am working on WPF application, I want create one user control that contain one grid with 5 columns and i want to repeat this control on WPF window form according to data fetched from database. It might be repeat one time or more than one.
the ItemsControl (or List) may help you here. You can bind the ItemsSource Property to your ViewModel IEnumerable Property where your DBEntries are stored.
With the ItemsControl.ItemTemplate Property you can define what DataTemplate is used for each Item of the Enumeration.
KR,
incureforce
I'm trying to make a search application using a wpf and entity framework following mvvm design patterns. When you search for someone, I want the ListBox to dynamically hold as many datagrids, as the search shows up. The datagrid will hold information such as first and last name, as well as a profile picture. I am kind of new to wpfs and c# in general, but I was thinking that the datagrid with all its information would be its own xaml. Then somehow I could add that xaml to the listbox as many times as I needed to(depending on the number of search results). Any help would be much appreciated.
Easy one: ListBox.ItemTemplate. The DataGrid XAML goes in the item template.
The search results go in an ObservableCollection of your search result class. That collection will be a member of your viewmodel, and in XAML you'll bind the collection to ListBox.ItemsSource.
The ListBox will instantiate the ItemTemplate once for each item in the search results collection.
Don't forget to implement INotifyPropertyChanged on your viewmodel, and raise PropertyChanged when you replace the collection with a new one. Changes to the collection's contents aren't your problem: use an ObservableCollection and it'll raise its own notifications for adds and removes. The ListBox will subscribe to those notifications without being asked.
I'm not being able to update a single item's DataTemplate on a list during runtime. In detail, here is what I'm trying to accomplish.
I have a Listbox where the items can have different states (Collapsed, expanded, disabled, etc), each with a different layout. I'm using a TemplateSelector to choose the correct DataTemplate according to a property on my class and that's working all great when I first create the list, the items are shown properly. However, when I change the property that sets the DataTemplate in runtime, the NotifyPropertyChanged is called and the information of the item is updated on the list, but not the DataTemplate. For example: I have a collapsed item with a label X that i want to expand. I click on the item and the label changes to Y but the DataTemplate doesn't update.
Any idea on how I can do this? Can't the DataTemplate be updated during runtime unless it is for the whole list?
I'll appreciate any help.
Make UserControl and use it inside your data template. Now, to change the state you can call methods on this UserControl and it will update. You can use animations via storyboard too.
I am running into an issue where i am using a panorama control and binding it to a datasource. But i still do want other custom items on another panorama items where i need a textblock, a grid and so on. So if i am adding it in the backend it doesnt show up those panorama items. It just shows the datasource binded items. Why is that so? Both of them should work out.
Can anybody help me with a solution for this.
Thank You.
Since you're wanting to manually add PanoramaItems, I can think of two approaches:
Make sure your Panorama.ItemsSource is set to an ObservableCollection that is accessible in the code behind or viewmodel, and then add your new items to that ObservableCollection which should update the Panorama.
Don't databind the Panorama control's Items - just add items manually when you want them.
Either way, the Panorama's ItemTemplate gets evaluated when the items are added to the underlying collection, so using a DataTemplateSelector will allow your code to determine which DataTemplate to apply when the new item is added without affecting the templates for previous items.
/chris
I have WPF listview bound to collection of objects. Objects are continuously added in to collection from remote server and same is reflecting in to listview. Now we have requirement that we should be able to freeze listview for some time,
That is objects should still get added in to collection but should not appear in listview till we unfreeze it ( we have button to freeze and unfreeze) . What is the best way to do it, when listview is bound to collection ? How to unbind collection and rebind it ? and Will i still able to filter and sort when collection is unbound from listview ? Waiting for answer please reply
Regards
Sandeep
You can just break the binding. In your freeze button handler say:
listView = _list
Which will freeze it at that point. Then in your unfreeze handler set the binding back up:
listView.SetBinding(ListView.ItemsSourceProperty, New Binding("_list"))
I hope this helps.
You should just stop updating the collection when the list is frozen, if you must keep adding to the collection even when the list is frozen (if the same collection is used somewhere else that shouldn't be frozen) then consider having two collections, one always updated and the other one bound to the listview.
What is the list type you are using as the data-source? Can you use BindingList<T>? If so, this has a settable RaiseListChangedEvents property, allowing you to turn off notifications. This will probably get very messy re your last points, though (sort/filter).
Personally, I'd work with 2 lists - the bound one, and the one that the server is updating. When paused, simply stop pumping data between the two. This should leave the paused view free for sorting / filtering etc.