Can I create a WPF custom controll that has a "placeholder" item?

Question

Hi all,

We have a lot of controls that consist of: A container with rounded borders and a couple of buttons that call save & cancel commands on the view model somthing like this:

     <Border Background="White" CornerRadius="10" BorderBrush="Black" BorderThickness="1" Opacity="1" Padding="5,5,5,5" VerticalAlignment="Center" HorizontalAlignment="Center">
        <StackPanel>
           <!--Some Control Stuff Here...-->

          <controls:SaveCancelButtons/>
        </StackPanel>
    </Border>

What I'd like to do is make a custom control/style/template etc that allows me to reuse this so I can just wrap any new user control in a set of tags that places its content into the stack panel (where the comment is above)

What's the best way of achiving this?

EDIT:

OK Now I have a template like so:

<ControlTemplate x:Key="RoundedBordersTemplate">
    <Border Background="White" CornerRadius="10" BorderBrush="Black" BorderThickness="1" Opacity="1" Padding="5,5,5,5" VerticalAlignment="Center" HorizontalAlignment="Center">
        <StackPanel>
            <ContentPresenter/>

            <controls:SaveCancelButtons/>
        </StackPanel>
    </Border>
</ControlTemplate>

And the control is implimented like so:

<ContentControl Template="{StaticResource RoundedBordersTemplate}">
            <StackPanel>
                <StackPanel Orientation="Horizontal">
                    <Label Content="Description: " Width="72"/>
                    <TextBox Text="{Binding Path=Description}"
                        Width="205" />
                </StackPanel>
                <StackPanel Orientation="Horizontal">
                    <Label Content="Type:" Width="72" />
                    <ComboBox ItemsSource="{Binding Path=TypeList}" 
                          DisplayMemberPath="Description" 
                          SelectedValuePath="ID"
                          Width="205" />
                </StackPanel>                
            </StackPanel>            
        </ContentControl>

But I only see the Save/Cancel buttons.

Answer 1

Your control should inherit from ContentControl (Control that contains CONTENT - i.e. other controls). Like all proper WPF controls this control is TOTALLY INVISIBLE - and the other stuff (buttons visual appearance) is added via the templating / styling mechanism.

Your subclass of ContentControl is then responsible for actually providing the logic for the buttons.

Answer 2

I would suggest using a ControlTemplate for type ContentControl:

<ControlTemplate x:Key="RoundedBordersTemplate" TargetType="ContentControl">
        <Border Background="White" CornerRadius="10" BorderBrush="Black" BorderThickness="1" Opacity="1" Padding="5,5,5,5" VerticalAlignment="Center" HorizontalAlignment="Center">
            <StackPanel>
                <ContentPresenter />
                <controls:SaveCancelButtons/>
            </StackPanel>
        </Border>
    </ControlTemplate>

Then use it as below:

<ContentControl Template="{StaticResource RoundedBordersTemplate}">
        <StackPanel>
            <Button>Hello</Button>
            <Button>World</Button>
        </StackPanel>
    </ContentControl>

To give you:

Update: this has the advantage of not requiring you to subclass ContentControl for a View-only change