I have a databound ListBox with an ItemTemplate, following this example:
<ListBox ItemsSource="{Binding Path=FlightHeadings}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Path=Identifier}" />
<TextBlock Text="{Binding Path=Name}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The ItemsSource databinding works; the ListBox displays all the items in the FlightHeadings property of the context.
However, the ItemTemplate is ignored. Instead of displaying each item as consisting of two TextBlocks, each item is instead displayed simply as its ToString() representation.
FWIW, I'm running Silverlight 4.0 on VS 2010, serving the test page with Cassini. I suspect I'm missing something very simple in the above XAML but I can't tell what it is; any advice would be greatly appreciated.
Turns out that the XAML is okay; the issue is that an old build of the XAP file was being displayed.
Purging the browser cache, restarting the development web server, and restarting the browser fixed the problem.
Related
We are working on an application using the MVVM architectural style (WPF) and facing an issue.
Before using WPF we have worked with WinForms and we used CheckedListBox. But now we are unable to find such control in WPF.
We are also using Infragistic toolkit.
Please provide any kind of help. Any lead will be appreciable.
You can take a Listbox and give it a Template with a Checkbox in.
Something like:
<ListBox ItemsSource="{Binding MyItems}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding IsSelected}" Content="{Binding}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
This looks like this:
Edit: The Items must have a Property "IsSelected" or you have to Wrap them in a SelectableItem helper class, which holds the original Item and a IsSelected Property.
I want to implement a ListBox which each item include a Image control and some other controls, then use it to binding some data. Due to this ListBox need to contains more than 2000 items, this means I have to do some optimization for it.
First, I noticed that most of the Image controls has one same picture(Default avatar), so I create a singleton ImageSource-object for the data. But although the Image control's source is the same object, you know I also need to create 2000 Image control in the ListBox with DataTemplate below:
<ListBox ItemsSource="{Binding Items}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<Image Source="{Binding Avatar}" />
<TextBlock Text="{Binding Name}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Is there have a way to reduce Image control object's number in my program? Thank you!
Ok, sounds odd, and there's likely a better way, but I haven't seen it yet.
What I'm trying to do is restyle a ListPicker under Windows Phone 7.
What I need is to
get rid of the header (that's easy, just define a null ListPicker.HeaderTemplate).
Force the picker to always go to full mode when clicked (again, easy, just set the ItemCountThreshold to 1).
Restyle the itemtemplate used when in FullMode (again, easy, just define a FullModeItemTemplate)
Incorporate the ListPicker's "HEADER" property value into the ItemTemplate (since only one item will ever show, i need the header text "embedded" within the one item).
It's that number 4 that I can't seem to get.
I've defined a listpicker like so (i'm directly defining the templates inline instead of in resources for now, just to keep things simple).
<phonekit:ListPicker Header="Header Text" x:Name="ListOfSounds"
SelectedItem="{Binding Path=DepartureChime, Mode=TwoWay, Converter={StaticResource EnumDescriptionToStringConverter}}"
ItemCountThreshold="1">
<phonekit:ListPicker.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Background="Transparent">
<TextBlock Text="{TemplateBinding Header}" />
<TextBlock Text="{Binding}" />
<TextBlock Text=">" />
</StackPanel>
</DataTemplate>
</phonekit:ListPicker.ItemTemplate>
Ignoring all the obvious formatting bits for now, the problem I'm having is that I can't use {TemplateBinding Header} from within a datatemplate. I've used it from a ControlTemplate no problem.
The result of this ItemTemplate should be an item displayed such as
{TextOfHeader}{Content of selected Item}>
I'm just not sure how to go about getting at a property of the templated control (the listpicker in this case).
Any ideas?
Take advantages of RelativeSource:
<TextBlock Text="{Binding Path=Header, RelativeSource={RelativeSource AncestorType={x:Type phonekit:ListPicker}}}" />
I have a Treeview in a Silverlight 4 project, and I want to bind to its SelectedItem. When I do a binding to SelectedItem (Mode=TwoWay) its throwing an error in blend because SelectedItem is readonly, which is causing my XAML to not render. I don't ever want to SET the SelectedItem property, I just want to know when it changes via UI interaction. In WPF, I would just bind its SelectedItem using Mode=OneWayToSource, but Silverlight does not support that mode (afaik).
Treeview :
<controls:TreeView ItemsSource="{Binding Repository.MajorClasses}" SelectedItem="{Binding SelectedItem, Mode=TwoWay}" />
Is there a workaround that anyone has used? And anyone know why OneWayToSource is omitted from Silverlight?
It's really readonly, so you cann't do that. You can use TreeView as base control and create CustomTreeView with implementation of bindable SelectedItem. Or create own behavior(attached property). Or use some third party control (f.i. telerik).
If you just want your VM to be informed when the user changes the selection, you should be able to do exactly what you are doing (a two way binding).
I have this working in Visual studio so, I suggest trying it from there, might just be a problem with Blend. VS intellisense doesn't suggest SelectedItem when typing in the XAML editor but that doesn't stop it from working.
The bound property in your VM is definately of the right type (MajorClass by the looks of it)?
What you need to do is make use of an Interaction Trigger and bind it to the SelectedItemChangedevent as follows:
<sdk:TreeView x:Name="ModuleNavigationItemWrappersTreeView" ItemsSource="{Binding ModuleNavigationItemWrappers}">
<sdk:TreeView.ItemTemplate>
<sdk:HierarchicalDataTemplate ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal" Margin="0,2,0,2">
<Image Source="/VanguardFinancials.Common;component/Images/icons/flag_blue.png" />
<TextBlock Margin="2,0,0,0" Text="{Binding ItemDescription}"></TextBlock>
</StackPanel>
</sdk:HierarchicalDataTemplate>
</sdk:TreeView.ItemTemplate>
<interactivity:Interaction.Triggers>
<interactivity:EventTrigger EventName="SelectedItemChanged">
<interactivity:InvokeCommandAction Command="{Binding TrackSelectedModuleNavigationItemWrapper}" CommandParameter="{Binding ElementName=ModuleNavigationItemWrappersTreeView}" />
</interactivity:EventTrigger>
</interactivity:Interaction.Triggers>
</sdk:TreeView>
Visit this for more information about Behaviors and Triggers. Hope this helps.
I have a probably simple problem, that I just can't seem to figure out:
I've made an ItemsControl which has its datacontext set and shows the data as pairs of Checkboxes and TextBlocks:
<ItemsControl Name="listTaskTypes" Grid.Row="1" Grid.Column="2" Grid.RowSpan="2" ItemsSource="{Binding}" Margin="10,0,0,0" VerticalAlignment="Top" Loaded="listTaskTypes_Loaded">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Name="checkBoxTypeId" Tag="{Binding Path=TaskTypeID}"/>
<TextBlock FontSize="11pt" FontFamily="Helvetica" Text="{Binding Path=Text}" />
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
My problem is that in the Loaded event of the ItemsControl, the checkboxes do not exist yet. How can I get an event when the ItemsControl is completely loaded or is this not possible?
listTaskTypes.ItemContainerGenerator.StatusChanged event handler can give you the notification on each item created on the ItemsControl.
Yeah Loaded is just the ItemsControl loaded event, the items might not have created at that moment. Just curious as to what you are trying to achieve here?. I guess you are trying to get the instance of CheckBox in the code behind? There may be better way using binding to achieve what you are looking for.
Try the DataContextChanged event!
When the DataContext changes, the control should be Loaded, and you can be sure it has a DataContext set as well.
Hope this helps