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How to set style for ItemsPanel from outside?

I define a style to make all StackPanel green:
<Window.Resources>
<Style TargetType="StackPanel">
<Setter Property="Background" Value="Green" />
</Style>
</Window.Resources>
But if I use StackPanel as panel template then it's NOT green:
<UniformGrid>
<StackPanel /><!-- this one is green -->
<ItemsControl>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel /><!-- this one is not -->
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</UniformGrid>
Why? How to make it also green?

Either move the implicit Style to App.xaml or add resource that is based on the implicit Style to the ItemsPanelTemplate:
<ItemsControl>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<ItemsPanelTemplate.Resources>
<Style TargetType="StackPanel" BasedOn="{StaticResource {x:Type StackPanel}}" />
</ItemsPanelTemplate.Resources>
<StackPanel />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
Types that don't inherit from Control won't pick up implicit styles if you don't do any of this.

Setting user control position

Hello Stackoverflowers,
I'm using an ItemsControl and my elements are all drawn on the top left corner, which create to a gap between the actual position and the mouse position (where my elements should be). Relevant mouse positions are saved in view model.
<ItemsControl
ItemsSource="{Binding OverlayElementsList}"
Background="Transparent"
BorderBrush="Black"
BorderThickness="2">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style TargetType="ContentPresenter">
<Setter Property="Canvas.Left" Value="{Binding ElementName=X, Path=Client.OverlayElement.StartPoint}" />
<Setter Property="Canvas.Top" Value="{Binding ElementName=Y, Path=Client.OverlayElement.StartPoint}" />
</Style>
</ItemsControl.ItemContainerStyle>
<ItemsControl.Resources>
<DataTemplate DataType="{x:Type elements:OverlayElement}">
<ContentControl Content="{Binding View}" />
</DataTemplate>
</ItemsControl.Resources>
Here is one of the possible View binded in the ItemsControl.Resources :
<UserControl x:Class="Client.ImageOverlayElementView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:Genetec.CS.OverlayModule.Client"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance local:ImageOverlayElement}">
<Grid>
<Image
Source="{Binding ImageSource}"
Height="{Binding Height}"
Width="{Binding Width}"
Canvas.Left="{Binding StartPoint}"
Canvas.Top="{Binding EndPoint}"/>
</Grid>
</UserControl>
The Canvas.Left and Canvas.Top properties seem to be simply ignored, why ?

Possible to display images in a ListBox with multiple rows

I am trying to get images in a Listbox to display in a certain way.
Listbox now:
How i want:
As you can see i want the scroll bar to be down the side and there to be multiple columns and rows depending on the size of the listbox.

Define WrapPanel as ListBox's ItemsPanel:
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel ></WrapPanel>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
Don't forget to set Width or MaxWidth to the wrap panel. Once max width is reached it will start placing content on new line...

use WrapPanel with Width set to a value. for an example run below code:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525" >
<Window.DataContext>
<local:ParentViewModel />
</Window.DataContext>
<ListBox Height="auto" ItemsSource="{Binding MyList,Mode=TwoWay}">
<ListBox.Style>
<Style TargetType="{x:Type ListBox}">
<Setter Property="ItemTemplate" >
<Setter.Value>
<DataTemplate>
<Button Content="{Binding}" Padding="15,5" Margin="100,40,0,0"
Command="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBox}},Path=DataContext.RemoveButtonCommand}"
CommandParameter="{Binding}"
/>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.Style>
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Width="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Window}},Path=ActualWidth}"
>
</WrapPanel>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
You will get both vertical and horizontal scrollbars. both adjusting according to height and width of window with the elements in listbox. (please bind your own listbox source)

Could someone give me some adviceabout WPF?

I am making a user control that is databound. The query results include a collection of objects (A) where A has a collction of other results (B). So A contains multilple B.
in the user control I want to represent the collection A as expanders and B as buttons inside of the expanders. This is what I got
<UserControl x:Class="GuideLib.ModuleControls.uclQuestions"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<ItemsControl x:Name="ictlAnswers" ItemsSource="{Binding}" Background="Gray">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Expander ExpandDirection="Down" Background="DarkGray">
<Expander.Header>
<TextBlock Text="{Binding Path=Name}" Foreground="White"/>
</Expander.Header>
<ListBox x:Name="SubListBox" ItemsSource="{Binding Path=Question}" Background="Gray" Foreground="White" HorizontalAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch">
<Button Content="{Binding Path=Name}" Margin="10,2,2,2" HorizontalAlignment="Stretch" Tag="{Binding Path=ID}">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="Gray" />
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="Orange" />
</Trigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
I have multiple problems.
1: I can not get the buttons in the expanders to strech horizontally
2: How can I set the Tag property of the button to be the whole object of B
3: Why does the default mouseover effect still execute.
Thanks

Ok here goes:
1. You need to set HorizontalContentAlignment="Stretch" on the ListBox and on the StackPanel inside DataTemplate set Orientation="Vertical"
2. set Tag="{Binding .}" on the Button
3. Update your Button.Style to something like:
<Button.Style>
<Style TargetType="{x:Type Button}">
<Setter Property="Background"
Value="Gray" />
<Setter Property="OverridesDefaultStyle"
Value="True" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border Background="{TemplateBinding Background}">
<ContentPresenter />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver"
Value="True">
<Setter Property="Background"
Value="Orange" />
</Trigger>
</Style.Triggers>
</Style>
</Button.Style>
finally before you add Question 4. remember ListBoxItem has a Style of it's own. So to completely override the effect on MouseOver when not on the Button but in the "Item" you have to provide a custom Style for ListBox.ItemContainerStyle
Oh and Start Using Snoop. It helps you debug Layout issues. Think you would have been able to solve problem 1 with it cos it would have shown you that your ContentPresenter of ListBoxItem was using required Width and not Stretching.

Just from taking a quick look at it.. for question 2 try doing this:
<Button Content="{Binding Path=Name}" Margin="10,2,2,2" HorizontalAlignment="Stretch" Tag="{Binding}">
That should make it bind to the items in the ListBox.

ToggleButton Checked Event Handling

I have ToggleButtons that are dynamically created based on my datasource. I would like to have only one togglebutton checked at a time when a user clicks one. How can I accomplish this?
<UserControl.Resources>
<ItemsPanelTemplate x:Key="HorizontalMiniDrawerList">
<StackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
<DataTemplate x:Key="MiniDrawerRowTemplate">
<ToggleButton x:Name="_MiniDrawerButton" Width="60" Height="85" Style="{DynamicResource MiniDrawerButtonWhite}" Checked="_MiniDrawerButton_Checked" >
</ToggleButton>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding Width}" Value="3">
<Setter TargetName="_MiniDrawerButton" Property="Width" Value="185"/>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
<DataTemplate x:Key="MiniDrawerListItemTemplate">
<ListBox SelectionMode="Multiple" Background="#00000000" BorderThickness="0" Width="500"
ItemsPanel="{StaticResource HorizontalMiniDrawerList}"
ItemTemplate="{StaticResource MiniDrawerRowTemplate}"
ItemsSource="{Binding Row}" >
</ListBox>
</DataTemplate>
</UserControl.Resources>
<Grid Background="{DynamicResource ListBackgroundColor}" >
<ListBox x:Name="_MiniDrawerRows" BorderThickness="0" Background="Transparent" Margin="107,84,225,217" ScrollViewer.HorizontalScrollBarVisibility="Disabled"
ItemsSource="{Binding Path=MiniDrawerRows, diagnostics:PresentationTraceSources.TraceLevel=High}"
ItemTemplate="{StaticResource MiniDrawerListItemTemplate}" >
</ListBox>
</Grid>
Update: Instead of using a togglebutton I used a radiobutton and changed the style of the radio button to look like a togglebutton.
<Style x:Key="MiniDrawerButtonWhiteRadioToToggleButton" BasedOn="{StaticResource {x:Type ToggleButton}}" TargetType="{x:Type RadioButton}">

I assume you mean "only one" instead of "only when". In that case you can use RadioButton (which is derived from ToggleButton) instead and set a GroupName on _MiniDrawerButton in your ItemTemplate. It looks like you are probably already using a custom ControlTemplate so you can use the same one for RadioButton by just changing the Style and ControlTemplate TargetTypes.