<Style TargetType="{x:Type local:FlipPanel}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:FlipPanel}">
                    <Grid >
                        <Grid >
                            <Grid x:Name="Grid1">
                                <ContentPresenter Content="{Binding Front," & _
                                  "RelativeSource={RelativeSource" & _
                                  "TemplatedParent}}" />
                            </Grid>
                            <Grid x:Name="Grid2">
                                <ContentPresenter  Content="{Binding Back," & _
                                  "RelativeSource={RelativeSource" & _
                                  "TemplatedParent}}" />
                            </Grid>
                        </Grid>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

Imports System.Windows.Controls.Primitives
Imports System.ComponentModel
 
Public Class FlipPanel
    Inherits ContentControl
 
    Public Shared ReadOnly FrontProperty As DependencyProperty = _
      DependencyProperty.Register("Front", GetType(object), GetType(FlipPanel), _
      New UIPropertyMetadata(Nothing))
    Property Front As object
        Get
            Return GetValue(FrontProperty)
        End Get
        Set(value As object)
            SetValue(FrontProperty, value)
        End Set
    End Property
 
    Public Shared ReadOnly BackProperty As DependencyProperty = _
      DependencyProperty.Register("Back", GetType(Object), GetType(FlipPanel), _
      New UIPropertyMetadata(Nothing))
    Property Back As object
        Get
            Return GetValue(BackProperty)
        End Get
        Set(value As object)
            SetValue(BackProperty, value)
        End Set
    End Property
 
 Shared Sub New()
        DefaultStyleKeyProperty.OverrideMetadata(GetType(FlipPanel), New _
          FrameworkPropertyMetadata(GetType(FlipPanel)))
    End Sub
End class

       <FlipPanel>
            <FlipPanel.Front>
                    <Button >
                        Front
                    </Button>
            </FlipPanel.Front>
            <FlipPanel.Back>
                <Button >Back</Button>
            </FlipPanel.Back>
        </FlipPanel>