Ok, this is an embarassingly simple-looking problem, but is driving me crazy. I'm learning about DataTemplating and am trying to apply a very VERY simple ItemTemplate to a ListBox.
However, when I run my app, the template is completely ignored and I just get the standard-looking listbox, whereas in fact I'd expect to see a list of checkboxes with 'Test' along side.
I've tried this several times and always the same result. I've checked several resource on Google and all have the same kind of syntax for defining and ItemTemplate on a ListBox, so I really cannot see where I'm going wrong.
Code...
<Grid x:Name="LayoutRoot">
<ListBox x:Name="TestList"
SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox Content="Check this checkbox!"/>
<TextBlock>Test</TextBlock>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.Items>
<ListBoxItem>Bob</ListBoxItem>
<ListBoxItem>Jim</ListBoxItem>
<ListBoxItem>Dave</ListBoxItem>
<ListBoxItem>Larry</ListBoxItem>
<ListBoxItem>Tom</ListBoxItem>
</ListBox.Items>
</ListBox>
</Grid>
Any help greatly appreciated. Sorry for such a dumb-seeming question, but I've really fallen at the first hurdle here :(
AT
ItemTemplate wont work when you put ListBoxItem directly as items. General concept is you databind a CRL collection to the ListBox.ItemsSource and then specify the ItemTemplate. Check the below code.
<Grid x:Name="LayoutRoot">
<ListBox x:Name="TestList" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox Content="Check this checkbox!"/>
<TextBlock Text="{Binding}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.Items>
<sys:String>Bob</sys:String>
<sys:String>Jim</sys:String>
<sys:String>Dave</sys:String>
<sys:String>Larry</sys:String>
<sys:String>Tom</sys:String>
</ListBox.Items>
</ListBox>
</Grid>
where sys is xmlns:sys="clr-namespace:System;assembly=mscorlib"
In this way, there are 5 ListBoxItems getting generated in the background and added to the ListBox.
You can use ItemContainerStyle instead of ItemTemplate if you want to add ListBoxItems directly to the ListBox.
Doing so, however, is only recommended when you need unique characteristics on a per item level.
If you are planning on all the items looking the same or making a dynamic list using ItemsSource, I would recommend you add strings (or another custom object) to your list and use ItemTemplate to display your items. (see Jobi Joy's answer)
Here's an example using ItemContainerStyle:
<ListBox
x:Name="TestList"
SelectionMode="Multiple">
<ListBox.ItemContainerStyle>
<Style
TargetType="ListBoxItem">
<Setter
Property="Template">
<Setter.Value>
<ControlTemplate
TargetType="ListBoxItem">
<StackPanel>
<CheckBox
Content="Check this checkbox!" />
<TextBlock
Text="{TemplateBinding Content}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.Items>
<ListBoxItem>Bob</ListBoxItem>
<ListBoxItem>Jim</ListBoxItem>
<ListBoxItem>Dave</ListBoxItem>
<ListBoxItem>Larry</ListBoxItem>
<ListBoxItem>Tom</ListBoxItem>
</ListBox.Items>
</ListBox>
For some reason DataTemplate can still be ignored if the ListBox is populated using ItemsSource e.g:
<ListBox Name="Test" x:FieldModifier="public" ItemsSource="{Binding UpdateSourceTrigger=PropertyChanged}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding Text, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Note that this is bound to an ObservableCollection containing objects (TextAdapter : INotifyPropertyChanged) with one property: string Text {...}
Related
ComboBox items were not displaying, if we try to keep that combobox in an ItemsCotrol. Please click here for understanding my requirement
My requirement is to keep a combobox in an ItemsControl, so that the ItemsControl qill be having 5 Comboboxes in it and each combox will be having a collection of items which we can select. So for that i tried with the below code and able to get the comboboxes in the ItemsControl, but the comboboxes collection is getting filled, any suggestions or workaround please..
<xamDataPresenter:Field Label="Reqs" BindingType="Unbound" Row="0" Column="4">
<xamDataPresenter:Field.CellValuePresenterStyle>
<Style TargetType="{x:Type xamDataPresenter:CellValuePresenter}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type xamDataPresenter:CellValuePresenter}">
<ItemsControl Name="I" ItemsSource="{Binding Path=DataItem.CollectionCount}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=DataItem.Collection}"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</xamDataPresenter:Field.CellValuePresenterStyle>
</xamDataPresenter:Field>
Ok, I've written up the most basic of ItemsControl to try and explain how these things work, which you can hopefully adapt for whatever your using for your dataitems.
So in your window's resources i've created a datatemplate. This respresents a repeating step and will be based on a DataItem. In this case my DataItem has 2 properties: DataItemProperty(string) and SelectedItem. The SelectedItem will have the same DataType of whatever it is your planning on showing in the combobox.
<DataTemplate x:Key="StepTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<TextBlock Text="{Binding Path=DataItemProperty}" Grid.Column="0"/>
<ComboBox Grid.Column="1" ItemsSource="{Binding Path=DataContext.ItemsToSelectFrom, Mode=OneWay, RelativeSource={RelativeSource AncestorType=Window}}"
SelectedItem="{Binding Path=SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Grid>
</DataTemplate>
The combobox in this example will be getting a list of available options from the code behind/viewmodel and not the DataItem, but when you select something it updates the SelectedItem property on the DataItem.
Then to show your items:
<ItemsControl
Focusable="False"
ItemTemplate="{StaticResource StepTemplate}"
ItemsSource="{Binding Path=Steps, Mode=OneWay}" />
So Steps is a property in my codebehind/viewmodel that will determine how many 'rows' get displayed.
The itemsControl allows you to add repeating sets of data easily, without having to write the same xaml multiple times.
Hope that helps?
I'm trying to remove group headers for groups where the header title is empty. But I can not make the binding in HeaderContainerStyle work. Neither can I set visibility on the TextBlock in TemplateHeader 'cause that will leave a small space and not be completely invisible.
This is my XAML:
<Page.Resources>
<CollectionViewSource
x:Name="MenuItemsGrouped"
IsSourceGrouped="True"
Source="{Binding MenuItems}" />
</Page.Resources>
<ListView Grid.Row="1" Margin="0"
ItemsSource="{Binding Source={StaticResource MenuItemsGrouped}}"
IsSynchronizedWithCurrentItem="False"
SelectionMode="Single"
SelectedItem="{Binding SelectedItem, Mode=TwoWay}">
<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding Title}" />
</DataTemplate>
</GroupStyle.HeaderTemplate>
<GroupStyle.HeaderContainerStyle>
<Style TargetType="ListViewHeaderItem">
<Setter Property="Visibility" Value="{Binding GroupHeaderVisibility}"></Setter>
</Style>
</GroupStyle.HeaderContainerStyle>
</GroupStyle>
</ListView.GroupStyle>
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0" Orientation="Horizontal">
<TextBlock Text="{Binding Title}" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Does anyone have a solution - and maybe a reason the binding won't work?
EDIT:
Ok, it's is actually a limitation in Windows Store Apps and earlier Silverlight apps:
Windows Presentation Foundation (WPF) and Microsoft Silverlight
supported the ability to use a Binding expression to supply the Value
for a Setter in a Style. The Windows Runtime doesn't support a Binding
usage for Setter.Value (the Binding won't evaluate and the Setter has
no effect, you won't get errors, but you won't get the desired result
either). When you convert XAML styles from WPF or Silverlight XAML,
replace any Binding expression usages with strings or objects that set
values, or refactor the values as shared StaticResource values rather
than Binding-obtained values.
from http://msdn.microsoft.com/en-us/library/windows/apps/windows.ui.xaml.setter
And see also Silverlight: How to use a binding in setter for a style (or an equivalent work around)
Just try to bind the Visibility of the root element of HeaderTemplate.
<GroupStyle.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding Title}" Visibility = "{Binding GroupHeaderVisibility}" />
</DataTemplate>
</GroupStyle.HeaderTemplate>
It should work.Good luck!
[Edit]
I have figured out a solution, it's not very elegant, but it works. Here are the steps:
Add this xaml code to your ListView:
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
2.Get a copy of ContainerStyle of GroupStyle(Right click the Listview on the design surface.Select: "Edit GroupStyle"->"ContainerStyle"). Then remove this line from the attributes of ContentControl:
Margin = "4"
3.Apply the above ContainerStyle to your listview. It should work.
NOTE: Step 1 is necessary, because ContainerStyle is no longer honored on Windows 8.1 when ItemsPanel is an ItemsStackPanel(which is the default).
http://msdn.microsoft.com/en-us/library/windows/apps/dn263110.aspx
You are binding to the Visibility property which is of type Visibility. My guess is that the GroupHasHeader property is a boolean; you should use a Boolean to visibility converter.
The application I'm developing has a kind of accordion made of expanders but each exapnder acts independently rather than only allowing a single open item at a time. Each expander is related to an item in a collection in the view model.
My currently solution is to use a listbox and then bind the lists itemsource to the collection and have an item template render the expander and the exapnders contents.
The problem is that the listbox treats each expander as an item (obviously) and allows selection and highlighting. Highlighting is a little ugly and could be disabled, but the selection causes me some issues because it causes the list to scroll to show as much of the expanded expander as possible.
Is there a WPF control that is a little like a stackpanel (perhaps) that would allow me to bind the contained controls using item templating but without the selection and highlighting?
<ListBox Grid.Row="0" Grid.Column="0" Width="Auto" SelectionMode="Single" ItemsSource="{Binding Path=MeasurementSources}">
<ListBox.ItemTemplate>
<DataTemplate>
<Expander Header="{Binding Name}" IsEnabled="{Binding Available}">
<ListBox Width="Auto" SelectionMode="Single"
ItemsSource="{Binding Path=Measurements}"
SelectedItem="{Binding Path=SelectedMeasurement}">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
<TextBlock Text=" "/>
<TextBlock Text="{Binding Created}"/>
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
If you want List-like capabilities without selection capabilities, you should use an ItemsControl - incidentally the base class of Selector which in turn is the base class of ListBox
The whole thing then just becomes
<ItemsControl Width="Auto" ItemsSource="{Binding Measurements}"
<ItemsControl.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
<TextBlock Text=" "/>
<TextBlock Text="{Binding Created}"/>
</WrapPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Obviously, you cannot bind a selected item in this case.
This is a useful piece of information that I had not realised.
http://msdn.microsoft.com/library/windows/apps/hh780657.aspx
Note ItemsControl is the base class for several common collection
controls, including ListView, GridView, FlipView, ListBox, and
ComboBox controls. These examples use the ListView and GridView
controls, but the info applies generally to ItemsControls.
In other words using the ItemsControl really is the way to solve my issue because using a ListBox and then trying to disable the highlight and the selection functionality really is turning it back into it's own base class.
The best solution is for me:
<Style TargetType="{x:Type ListBoxItem}">
<Style.Resources>
<!-- With focus -->
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}"
Color="Transparent" />
<!-- Without focus -->
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}"
Color="Transparent" />
<!-- Text foreground -->
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}"
Color="Black" />
</Style.Resources>
<Setter Property="FocusVisualStyle" Value="{x:Null}"></Setter>
</Style>
and I found it few months ago somwhere on stackoverflow :)
I have a listbox where I have to add about 20 static custom items. All the items are based on the same template (something like that) :
<Border>
<StackPanel Orientation="Horizontal">
<Image Source="" Height="30" />
<TextBlock Text="" VerticalAlignment="Center" />
</StackPanel>
</Border>
I don't want to repeat that 20 times in the ListBox.Items I would like to have some kind of UserControl where I could do something Like the following where I could set some custom properties :
<ListBox>
<ListBox.Items>
<MyListBoxTemplate x:Name="Item1" ItemText="Item #1" ItemImageSource="/Image1.jpg" />
<MyListBoxTemplate x:Name="Item2" ItemText="Item #2" ItemImageSource="/Image2.jpg" />
...
</ListBox.Items>
</ListBox>
But I don't wan't to create a userControl just for that!!! Is there an easy way to put that template in the Window.Resources?
Thanks
If you are ONLY using it for that SPECIFIC listbox, you can just assign the ItemTemplate property. This will need to work in conjunction with a collection of custom objects defined in your resources somewhere else. This will save you from creating a custom UserControl, but you will need an object that can be defined in XAML and a list of them in XAML anyway. To be honest, creating a UserControl is relatively painless and may be easier, but it is possible without doing so.
<ListBox>
<ListBox.ItemTemplate>
<DataTemplate TargetType="CustomObjectType">
<Border>
<StackPanel Orientation="Horizontal">
<Image Source="{Binding ImageSource}" Height="30" />
<TextBlock Text="{Binding TextContent}" VerticalAlignment="Center" />
</StackPanel>
</Border>
<DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
EDIT: If you are going to use it in more than one place, put the DataTemplate in your Application resources and ive it a key, then assign the ItemTemplate property to {StaticResource MyListBoxItemsTemplateKey}
Not my favorite approach since it uses the XmlDataProvider and XPath syntax (which I tend to always forget). But you can embed your static data as xml within your Window.Resources like so:
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Window.Resources>
<XmlDataProvider x:Key="MyStaticData" XPath="StaticItems" >
<x:XData>
<StaticItems xmlns="">
<StaticItem>
<ItemText>Item #1</ItemText>
<ItemImageSource>/Image1.jpg</ItemImageSource>
</StaticItem>
<StaticItem>
<ItemText>Item #2</ItemText>
<ItemImageSource>/Image2.jpg</ItemImageSource>
</StaticItem>
</StaticItems>
</x:XData>
</XmlDataProvider>
</Window.Resources>
<Grid>
<ListBox>
<ListBox.ItemsSource>
<Binding Source="{StaticResource MyStaticData}" XPath="StaticItem" />
</ListBox.ItemsSource>
<ListBox.ItemTemplate>
<DataTemplate>
<Border>
<StackPanel Orientation="Horizontal">
<Image Source="{Binding XPath=ItemImageSource}" Height="30" />
<TextBlock Text="{Binding XPath=ItemText}" VerticalAlignment="Center" />
</StackPanel>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Window>
Then within your ListBox bind to the XmlDataProvider you specified and use the XPath notation within the bindings to drill down to the data you want the controls to bind to.
This site has a couple good examples too:
http://vbcity.com/blogs/xtab/archive/2010/12/24/more-xpath-examples-in-a-wpf-application.aspx
Hope this helps!
I have a WPF listbox which displays messages. It contains an avatar on the left side and the username and message stacked vertically to the right of the avatar. The layout is fine until the message text should word wrap, but instead I get a horizontal scroll bar on the listbox.
I've Googled and found solutions to similar issues, but none of them worked.
<ListBox HorizontalContentAlignment="Stretch" ItemsSource="{Binding Path=FriendsTimeline}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Border BorderBrush="DarkBlue" BorderThickness="3" CornerRadius="2" Margin="3" >
<Image Height="32" Width="32" Source="{Binding Path=User.ProfileImageUrl}"/>
</Border>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Path=User.UserName}"/>
<TextBlock Text="{Binding Path=Text}" TextWrapping="WrapWithOverflow"/> <!-- This is the textblock I'm having issues with. -->
</StackPanel>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Contents of the TextBlock can be wrapped using property TextWrapping.
Instead of StackPanel, use DockPanel/Grid.
One more thing - set ScrollViewer.HorizontalScrollBarVisibility property to Disabled value for the ListBox.
Updated Hidden to Disabled based on comment from Matt. Thanks Matt.
The problem might not be located in the ListBox. The TextBlock won't wrap, if one of the parent controls provides enough space, so that it hasn't the need to wrap. This might be caused by a ScrollViewer control.
If you want to prevent TextBlock to grow, and you want it to just fit in the size of the listbox, you should set the width of it explicitly.
In order to change it dynamically, it means not a fix value, but you need to bind it to its proper parent element in the visual tree. You can have something like this:
<ListBox ItemsSource="{Binding MyItems}" Name="MyListBox">
<ListBox.Resources>
<Style TargetType="ListBoxItem">
<Setter Property="Width"
Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ScrollContentPresenter}, Path=ActualWidth}" />
</Style>
</ListBox.Resources>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Title}" TextWrapping="Wrap" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
If it does not work, try to find the proper elements (which has to be binded to what) with the Live Visual Tree in Visual Studio.