ListBox of anonymous UIElements - c#

I want to create a ListBox and fill it with anonymous UIElement. In other words, the DataTemplate of the ItemTemplate will contain only one element, and afterwords during the runtime, afterwards I will create in the code behind different UIElements (TextBlocks, Grids ...) and populate the list with it.
So how am I going to write the DataTemplate of the ListBox? And how am I intend to use an ObservableCollection for the ItemSource? So should use an ObsevableCollection of UIElement?

First Question: No DataTemplate. Since your items are already UIElements, you don't need a DataTemplate.
And if you're creating a changeable collection, then yes, ObservableCollection<UIElement> is the way to go.
Now, why would you be doing this? You may want to ask yourself if this is the best way of doing things. Why isn't your data and your presentation separated? If you need more than one type of element in the list, will DataTemplateSelector allow you to have a real ViewModel?

<ListBox x:Name="name" ItemsSource="{Binding source}">
<ListBox.ItemTemplate>
<DataTemplate>
<textbox x:Name="name"></ToggleButton> //or any tool
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

Related

how to add user controls as listbox items

I am using WPF .net 4.5 (c#) and I would like to make a ListBox that contains a series of user controls. (If a listbox is the wrong type of control, please let me know).
I want my listbox to have a copy of the user control as the list items, with different contents within each one.
How do I add user controls to a listbox?
Thanks for your help in advance!
You can set ItemTemplate for the listbox with your usercontrol in it.
<ListBox>
<ListBox.ItemTemplate>
<DataTemplate>
<local:UserControl1/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Thanks
I think you can design a DataTemplate which ha the same UI or Style as this UserControl .
maybe just copy paste can get a DataTemplate as you want,however
<DataTemplate>
<local:UserControl1/>
</DataTemplate>
this king seems very strange for me I dont konw it can work as you want,so I also want to know
the answers。

how to add two different controls (checkbox and combobox) as list item in ListBox wpf

I need to bind the listbox with list of items retreived from database. Each list item is displayed as checkbox in listbox.
<ListBox.ItemTemplate>
<HierarchicalDataTemplate>
<CheckBox Content="{Binding Name}" IsChecked="{Binding IsChecked}"/>
</HierarchicalDataTemplate>
</ListBox.ItemTemplate>
Along with the checkbox, I also need to add a checkbox as a list item.
Could anyone let me know as to how this can be done?
DataTemplateSelector options within WPF this allow a very small amount of backend code to take care of all the selections for you. This allows you to make use of this code from within an MVVM structure without any issues, and while making the front end extremely easy to manage without complicating the back end code.
here is a sample.
Use DataTemplateSelector if you want to use two different visuals as list items.

Select an item from checkedlistbox using wpf,mvvm

I am new to MVVM, I have a checkedlistbox in a view with the list of titles(have bound the exposed property in ViewModel to this checkedlistbox control)...
Here is my XAML code that populates the ListCheckBox -
<ListBox x:Name="lstCode" ItemsSource="{Binding Code,Mode=TwoWay}" Grid.Row="1" Style="{StaticResource ListBoxStyle}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox x:Name="chkBox" IsChecked="{Binding IsChecked,Mode=TwoWay}" Content="{Binding Code_Name}" Margin="0" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
This control shows the correct list of items with checkboxes for each item in the listbox...
What should be the code in viewmodel to make it work in two way - while getting the codes from database, it should automatically selected the code from the listcheckedbox and when the user selects one or more codes, the viewmodel should be able to know the items selected...
In general, for TwoWay binding, you will need to implement the INotifyPropertyChanged interface on the ViewModel you want to bind to.
In this case, your ViewModel will have to provide a property that returns a collection that your view can bind to, e.g. an ObservableCollection.
This ObservableCollection already allows you to add, update, and delete items in that list in a way that automatically communicates the changes between View and ViewModel.
For the rest I suggest to start digging into MVVM depths. To fully take advantage of WPF's capabilities, you will need to understand the basics for yourself. A great starting point is this SO thread: MVVM: Tutorial from start to finish?

Parent-Child inside DataTemplate

In my MainWindow, I've got a ListBox whose ItemsSource is bound to an ObservableCollection of Layout POCO objects:
<ListBox x:Name="ListBox" ItemsSource="{Binding Layouts}">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel IsItemsHost="True" Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
Also, in the MainWindow, we define the visual representation of a Layout object using a UserControl (LayoutUserControl):
<DataTemplate DataType="{x:Type local:Layout}">
<local:LayoutUserControl />
</DataTemplate>
When we add objects to the Layouts collection, we see new LayoutUserControls populate the ListBox. This is pretty straight forward.
Now, what I'd like to do, is somehow communicate from the MainWindow to the individual LayoutUserControls. Specifically, from the MainWindow, I want to call a single method on each of the LayoutUserControls... If I attempt to iterate through the ListBox's Items collection, all I get is a reference to the Layout objects, not the LayoutUserControls. Since the LayoutUserControls are defined in a DataTemplate, I don't have a named reference to access them...
Is there a WPF construct that supports this type of interaction from parent to child controls? RoutedEvents were my first thought, but they only support child to parent (bubble) communication. Perhaps commands are the way to go?
Any help would be appreciated.
Thanks!
Yes, there is a method which you should never use, it's the ItemContainerGenerator.
You should, as you noted yourself, set up the communication differently, commands sound reasonable. Expose a command on the Layout and bind the UserControl to it. Or create an event and make the UserControl subscribe to it, then you can raise that.
In Silverlight there is an extension called GetItemsAndContainers as described in this SO question that does this but I cannot find an equivalent in WPF.
However it may still be possible as described in How can I access the ListViewItems of a WPF ListView? by using the VisualTreeHelper to get the LayoutUserControls inside the ListBox.

Data Binding Label Content to Array

I am somewhat new to WPF and Data Binding, it seems very powerful. I'm wondering if there's a way to have a set of labels, and have there Content property all binded to a different index in array of strings. So then as the array is updated, the labels automatically change too.
The xaml syntax is still a bit foreign to me and I haven't been able to get it to work.
If this is a dynamic set of labels, then you may be better off using an ItemsControl, and changing its ItemTemplate to display a label for each item in the collection that it is bound to (a collection of strings in your case).
Something like:
<ItemsControl ItemsSource="{Binding MyLabelStrings}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Label Content="{Binding}" ... />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
As Bojin mentions, if you wish your UI to update if strings are added/removed from the collection, then use an ObservableCollection for the MyLabelStrings property.

Categories