I'm doing some stuff in WPF.
I have a ComboBox with many Types. After selecting a concrete type, I want to be able to Load a particular UserControl (with many TextBoxes etc.) respecting the type in a defined region on my WPF Window.
How to do that? Is there anything like
LoadControl() and load it into a PlaceHolder in ASP.NET? And what's the best way of doing this?
Thanks.
You should create a DataTemplate for each type. See Different item template for each item in a WPF List for more information.
What about:
object o = Activator.CreateInstance(type);
myUserControl.PubliclyExposedContainer.Content = o;
Not really sure why you'd go to the trouble of creating a DataTemplate for each type.
Related
In wpf with mvvm I use a ListBox with Canvas as ItemsPanelTemplate and DataTemplates to customize appearance.
I would like to improve performance by first adding all items of type 1 to the drawing, then all items of type 2.
I could create two ListBoxes both with Canvas as ItemsPanelTemplate and they would be overlays.
Panning and scrolling could be synchronized by means of bindings.
This way I can raise PropertyChanges for both lists independantly from each other.
Question: do you have experience whether overlaying canvases is good or bad for performance?
I an not sure whether this is also possible using a CompositeCollection for the ItemsSource of one ListBox. Or for that matter give both types a common subclass and stay with ObservableCollection.
Question: do you think that somehow a list with CompositeCollection can be given separate PropertyChanges for different parts of the Collection?
EDIT:
Suppose I have a great number of points, lines, labels for the canvas, each of a different type, however with a common base type. I select the DataTemplate using DataType: DataType="{x:Type my:Point}", DataType="{x:Type my:Line}" etc.
First as quicly as possible I want the user to see the lines. I raise PropertyChanged("Lines") and the ListBox+Canvas for the lines is visible.
In a backgroundworker I raise PropertyChanged("Points") and the ListBox2+Canvas2 for the points is visible.
When done in another backgroundworker I raise PropertyChanged("Labels") and the ListBox3+Canvas3 for the labels is visible.
There's a much simpler solution using basic Object Oriented Programming. Create a base data type and make all of your data objects extend from it. It could be empty, but if nothing else, you could implement INotifyPropertyChanged in it so you don't have to in each of the other data types.
Then you simply add a property of type ObservableCollection<BaseClass> to your view model or code behind and data bind that to the ListBox.ItemsSource property. As long as you don't set the x:Key values on the different DataTemplates, then WPF will implicitly set them to the relevant data type objects when it renders them.
So you can put all of your different data types in the same collection. Then you can add your first type in and wait for however long and add some of a different type, or whatever order you feel like.
UPDATE >>>
In response to the edit in your question, I don't quite understand the reason for you trying to use the INotifyPropertyChanged interface to show the items, type by type. If you have the base class collection that I mentioned above, then you simply add the instances of the first type to the collection first, so they'll appear first. When you want the next type to appear, just add them into the collection and then they'll appear and so on. The ObservableCollection will take care of that.
I'm looking to represent a collection of different but related data types and give the user the chance to edit these. I can't represent them in a grid because each type is different and therefore doesn't lend itself to a grid layout.
e.g.
Type1 - properties are From, To, Threshold, Enabled
Type2 - properties are From, ExecutedPercent, Benchmark, Enabled
etc
These types are related but different so I'm thinking of creating a tool bar with the types along the top. When the user selects Type1 I generate the UI using a custom ItemTemplate on a ListBox, same for Type2. I am therefore swapping out the ItemTemplate at runtime and changing the data source.
Questions:
1. Does this sound like a reasonable approach?
2. Does it make sense to item template ListBox?
3. Are there any other controls I should think about templating here? It seems to me that ListBox is about the perfect candidate for any kind of List source when all the items need to be displayed.
Thanks in advance
In order to handle different types of items you can use ItemTemplateSelector which will be more clear WPF solution.
If you do not need having selected item in listbox and only need to display items then you should use ItemsControl instead of ListBox
you can use a datatemplateselecter so you dont have to set the itemtemplate when the type is switched just change the datasource.
Currently I have a UserControl that displays collections of data in the same layout. So one control could be instanced with a collection of ObjectA and another of ObjectB. I then use TemplateSelectors to choose the right DataTemplates.
Later on we thought we'd set the List as a GridView to show more information in the list itself. However each type of object has different properties and the columns may have different names and not the same quantity. I realized then that the columns and such where not set in the ItemTemplate but at the GridView itself and ListView of course has no templateSelector for itself.
I wasn't sure how to do it but several ways came into mind.
1) There is some kind of TemplateSelector property I'm not aware off.
2) I CAN set it somehow at the ItemTemplateSelector only don't know how.
3) I could do the GridView dynamically (could be difficult and wan't to avoid).
Any good way to do this, tutorials or similiar I could use?
EDIT:
As I have learned a little bit more about ListView and it's view property I'm pretty sure I could define the gridview in a staticResource. Still I would love a ViewSelector or something similar. I guess this was of course not intended as the the item could be dynamic while the Collection isn't.
But I'm thinking about cases where there could exist more types of view then gridview ( iconview or something else) and the user could switch between them it would have to be implemented in some way.
The solution I see know is using a trigger and basing it on the first item in the collection but I'm not liking that too much.
Have you looked at the AutoGeneratingColumns property of the Grid?
http://msdn.microsoft.com/en-us/library/system.windows.controls.datagrid.autogeneratingcolumn(v=vs.95).aspx
I'm working on a project where I have some hierarchical data that I want to be able edit through a fancy WPF control.
The data structure is essentially an expression tree. Each node can be a different Expression type but inheriting from the same base class. These different types need to have their own way of editing them.
My thoughts are that I would use the WPF TreeView control and then dynamically add editor controls for each type of Expression. I have only a basic understanding of WPF's data binding and the MVVM pattern so I'm not sure if this is possible to do or even where to begin. Any pointers or guidance would be greatly appreciated.
It sounds like what you're looking for is the HierarchicalDataTemplate class.
Greetings to all and sorry for my English!
I have a ListBox, it's ItemsSource = myClientsList.DefaultView. The Items of ListBox have a template (ControlTemplate), that is defined in a in a separate resource file.
Every Item contains a little TextBlock's, Text -property of each have a binding to fields of my Object myClientsList.
I need to add in a this item template more TexBlock's and each of them must have binding to fields of another my class myOrdersList. - (So I wish to view on each line of ListBox information from different tables of my database - this is a question).
Problem in that that ListBox's ItemsSource have a link to object myClientsList and I cann't set myOrderList to ItemSource of same ListBox. So i must find a way to specify TextBlock.DataContext wich inside ControlTemplate or how it's possible to solve this problem in another way?
p.s. I'm a new in .Net and WPF and probably have a mistakes in my explanation - sorry for it.
It sounds like you have a DataGrid type of display and want to add more columns in order to display the order information for a given client. If this is the case, you are going to have to do a couple of things. First, you will need to create a composite object that stores information for both entities into a single object (so each row of your control has all the data it needs to display). Secondly, I would recommend using an actual DataGrid control to display rows instead of templating a ListBoxItem. The ListView with a GridView built into the framework isn't great, so I would recommend the WPFToolkit's DataGrid for a free option.
There are two issues here, if I've understood the question: how do you create a single collection containing both Clients and Orders, and how do you display Clients and Orders in different ways within the same ListBox?
Regarding the first, you can do this using a CompositeCollection.
Regarding the second, define two DataTemplates instead of a ControlTemplate. As the key of each DataTemplate, use the type of the object it is going to present e.g.
<DataTemplate x:Key="{x:Type local:Client}">
Alternatively, use ItemsControl.ItemTemplateSelector to explicitly point at different DataTemplates depending on the type of item. Ot if you really have to use ControlTemplates, check out ItemsControl.ItemContainerStyleSelector.