win8 metro 弹出一个部分

    <Popup x:Name="AddItemPopup" IsLightDismissEnabled="True" Width="435" Height="265" >
        <StackPanel Background="Black">
            <Border Background="#85C54C" BorderThickness="4">
                <Grid Margin="10">
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="300"/>
                    </Grid.ColumnDefinitions>

                    <TextBlock Text="Name:" Style="{StaticResource AddItemText}"  />
                    <TextBlock Text="Quantity:" Grid.Row="1" 
                               Style="{StaticResource AddItemText}" />
                    <TextBlock Text="Store:" Grid.Row="2" 
                               Style="{StaticResource AddItemText}" />

                    <TextBox x:Name="ItemName" Grid.Column="1" 
                             Style="{StaticResource AddItemTextBox}" />
                    <TextBox x:Name="ItemQuantity" Grid.Row="1" Grid.Column="1" 
                             Style="{StaticResource AddItemTextBox}" />
                    <ComboBox x:Name="ItemStore" Grid.Column="1" Grid.Row="2" 
                              Style="{StaticResource AddItemStore}" 
                              ItemsSource="{Binding StoreList}" 
                              DisplayMemberPath="" />
                    <StackPanel Orientation="Horizontal" Grid.Row="3" 
                                HorizontalAlignment="Center" 
                                Grid.ColumnSpan="2">
                        <Button Click="AddButtonClick">Add Item</Button>
                    </StackPanel>
                </Grid>
            </Border>
        </StackPanel>
    </Popup>

控制弹窗的可见性 ：IsOpen属性 为true 是可见 ，false 不可见

弹出的位置为右下角