How do I space out the child elements of a StackPanel?

Question

Given a StackPanel:

<StackPanel>
  <TextBox Height="30">Apple</TextBox>
  <TextBox Height="80">Banana</TextBox>
  <TextBox Height="120">Cherry</TextBox>
</StackPanel>

What's the best way to space out the child elements so that there are equally-sized gaps between them, even though the child elements themselves are of different sizes? Can it be done without setting properties on each of the individual children?

Solution 1

Use Margin or Padding, applied to the scope within the container:

<StackPanel>
    <StackPanel.Resources>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Margin" Value="0,10,0,0"/>
        </Style>
    </StackPanel.Resources> 
    <TextBox Text="Apple"/>
    <TextBox Text="Banana"/>
    <TextBox Text="Cherry"/>
</StackPanel>

EDIT: In case you would want to re-use the margin between two containers, you can convert the margin value to a resource in an outer scope, f.e.

<Window.Resources>
    <Thickness x:Key="tbMargin">0,10,0,0</Thickness>
</Window.Resources>

and then refer to this value in the inner scope

<StackPanel.Resources>
    <Style TargetType="{x:Type TextBox}">
        <Setter Property="Margin" Value="{StaticResource tbMargin}"/>
    </Style>
</StackPanel.Resources>

Solution 2

Another nice approach can be seen here: http://blogs.microsoft.co.il/blogs/eladkatz/archive/2011/05/29/what-is-the-easiest-way-to-set-spacing-between-items-in-stackpanel.aspx Link is broken -> this is webarchive of this link.

It shows how to create an attached behavior, so that syntax like this would work:

<StackPanel local:MarginSetter.Margin="5">
   <TextBox Text="hello" />
   <Button Content="hello" />
   <Button Content="hello" />
</StackPanel>

This is the easiest & fastest way to set Margin to several children of a panel, even if they are not of the same type. (I.e. Buttons, TextBoxes, ComboBoxes, etc.)

Solution 3

I improved on Elad Katz' answer.

• Add LastItemMargin property to MarginSetter to specially handle the last item
• Add Spacing attached property with Vertical and Horizontal properties that adds spacing between items in vertical and horizontal lists and eliminates any trailing margin at the end of the list

Source code in gist.

Example:

<StackPanel Orientation="Horizontal" foo:Spacing.Horizontal="5">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

<StackPanel Orientation="Vertical" foo:Spacing.Vertical="5">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

<!-- Same as vertical example above -->
<StackPanel Orientation="Vertical" foo:MarginSetter.Margin="0 0 0 5" foo:MarginSetter.LastItemMargin="0">
  <Button>Button 1</Button>
  <Button>Button 2</Button>
</StackPanel>

Solution 4

The thing you really want to do is wrap all child elements. In this case you should use an items control and not resort to horrible attached properties which you will end up having a million of for every property you wish to style.

<ItemsControl>

    <!-- target the wrapper parent of the child with a style -->
    <ItemsControl.ItemContainerStyle>
        <Style TargetType="Control">
            <Setter Property="Margin" Value="0 0 5 0"></Setter>
        </Style>
    </ItemsControl.ItemContainerStyle>

    <!-- use a stack panel as the main container -->
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <StackPanel Orientation="Horizontal"/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>

    <!-- put in your children -->
    <ItemsControl.Items>
        <Label>Auto Zoom Reset?</Label>
        <CheckBox x:Name="AutoResetZoom"/>
        <Button x:Name="ProceedButton" Click="ProceedButton_OnClick">Next</Button>
        <ComboBox SelectedItem="{Binding LogLevel }" ItemsSource="{Binding LogLevels}" />
    </ItemsControl.Items>
</ItemsControl>

Solution 5

+1 for Sergey's answer. And if you want to apply that to all your StackPanels you can do this:

<Style TargetType="{x:Type StackPanel}">
    <Style.Resources>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Margin" Value="{StaticResource tbMargin}"/>
        </Style>
    </Style.Resources>
</Style>

But beware: if you define a style like this in your App.xaml (or another dictionary that is merged into the Application.Resources) it can override the default style of the control. For mostly lookless controls like the stackpanel it isn't a problem, but for textboxes etc you may stumble upon this problem, which luckily has some workarounds.

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Comments

[zar]

Really just adding padding to individual items seems to be best option.

[cwhisperer]

The scoped Style is an awesome way to do that - thanks for the tip!

[Armentage]

This is a pretty interesting way to go about this. It makes a lot of assumptions about exactly how you want to space things, and even gives you an opportunity to automatically adjust the margins on the first/last items.

[grv_9098]

What if i want to use it for entire project ?

[grv_9098]

<Style.Resources> Are u sure about it coz when i tried this it was showing error.

[Andre Luus]

Sorry, I can't remember off-hand. I'll have to try it myself to see. I'll get back to you.

[Andre Luus]

Yes, it does work. Just did the same to set TextWeight="Bold" on all TextBlocks in a StackPanel. Only difference was I set the style explicitly on the StackPanel.

[grv_9098]

Thanks for ur concern but I still have doubt.I know about that It called Scope Style. I guess it will be <StackPanel.Resources> and not <Style.Resources> . It will be more great if you can paste the code piece of your...

[Jack Ukleja]

Can someone explain why this only works when you explicitly define the type (e.g. TextBox)? If I try this using FrameworkElement so that all children are spaced, it has no effect.

[Adam McKee]

This doesn't work well if you've already defined a style for Button.

[Anthony Nichols]

As a side note, if you want to do this with a Label you have to use Padding instead of Margin

[IanJ]

Great tip, but this works better with the Style TargetType as "FrameworkElement" (otherwise it doesn't work for Image, for example)

[label17]

I like this idea. Just one addition: subtracting the amount of spacing from the margin of the StackPanel (Margin="0 0 -5 0") will also counter the spacing after the last item in the list.

[waxingsatirical]

The problem with this is that the style you set will override any other styles that you may already have on the Items. To overcome this see this related question/accepted answer here

[Xerillio]

+1 for versatility. Also to improve on the blog post, adding if (fe.ReadLocalValue(FrameworkElement.MarginProperty) == DependencyProperty.UnsetValue) before actually setting the margin of the child it allows to manually specify margins for some elements.

[Drew Noakes]

Note that this doesn't work if the child items are added/removed dynamically, such as in an ItemsControl bound to a changing collection.

[Drew Noakes]

Like Elad's answer, this doesn't work if the child items are added/removed dynamically, such as in an ItemsControl bound to a changing collection. It assumes the items are static from the moment the parent's Load event fires.

[Drew Noakes]

Also, your gist gives a 404.

[angularsen]

Updated link to gist.

[xtreampb]

I filled my stack panel with grids, and then set my target type to grid. My stack panel has Grid.IsSharedSizeScope="True" also allowing me to have grid shared size groups in my sub grids.

[Jonathan H]

Works when the panel is set as an ItemsPanelTemplate for an items control

[Paul]

@Mark Ingram I assume this is because of specificity?

[Paul]

This looks very elegant. Are there any significant downsides to this?

[Mr. Squirrel.Downy]

For @Mark Ingram and other peopel, Use Style.BaseOn property. BaseOn="{StaticResource {x:Type Button}}" can make it inheriting the parent style. for more info: stackoverflow.com/questions/44065383

[Battle]

In case it doesn't work: Build the project, otherwise it won't render the page.

[Admin]

What if I need to use margin for multiple items like Textbox, Button,..?

[Dave]

Link is broken!

[JoachimAlly]

This one is fantastic. Thanks, angulararsen.

[IAbstract]

If someone had asked how to achieve the result with a Grid, then this would be a good answer. The question was in regards to a StackPanel which has a nice answer below. Why do people insist on not answering the question proposed?

[Clonkex]

If only they would add these to WPF! It's honestly such a massive oversight.

[Clonkex]

@IAbstract What's wrong with this? It's not exactly what the OP asked for, but it also covers the case that the OP (or future Googlers) had a variant of the XY problem. I can't count the number of times a late, seemingly-tangentially-related answer to the question was actually the best answer.