在堆栈面板上填充? ？

You'll probably want to add margin to the items in the panel instead. You'll get the same result, just have to approach it backward.

You could put a Border around the StackPanel and set a padding on that. I end up doing this a lot, since there are many UIElements that do not have a padding property.

<Border Padding="10">
<StackPanel>
<!--...-->
</StackPanel>
</Border>

(Note: all FrameworkElements have a Margin property, which will space the element, but not include the margin width as part of the ActualWidth).

If you want to space the items inside a StackPanel, you'll want to add a margin to each child as Rob said.

Or you could do something similar to TiM:

<Border>
<StackPanel Margin="10">
...
</StackPanel>
</Border>

if you mean you want to space out child elements of the StackPanel (which doesn't have a Padding property), see: How do I space out the child elements of a StackPanel?

This is a variant of padding for elements of StackPanel

<StackPanel Orientation="Horizontal" Grid.Row="2">
<StackPanel.Resources>
<Style x:Key="StackPanelPadding" TargetType="Control">
<Setter Property="Margin" Value="5,0,0,0"/>
<Setter Property="Height" Value="40"/>
</Style>
<Style BasedOn="{StaticResource StackPanelPadding}" TargetType="Button"/>
</StackPanel.Resources>
<Button/>
<Button/>
</StackPanel>