WPF: Different content in StackPanel dependent on the DataContext's type

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Hello guys!
It's a pretty long time since my last WPF code, so this is probably an easy question I just don't know the answer to.
I have a TreeView that contains different types: Milestone, Issue, ProjectTask, etc.
Now dependent on the selected item I want to get an info panel filled.
I thought of something like this:

<StackPanel Orientation="Vertical" Grid.Column="1" DataContext="{Binding ElementName=ProjectTaskTreeView, Path=SelectedItem}">
    <TextBlock Text="{Binding Id}"></TextBlock>
</StackPanel>

This works fine for an Issue, but when I select a MileStone I want to show the property DisplayText instead of Id and another additional TextBlock.
How can I achieve this the "most easy" or "best practice" way?
Is something similar to the following possible?

<StackPanel Orientation="Vertical" Grid.Column="1" DataContext="{Binding ElementName=ProjectTaskTreeView, Path=SelectedItem}">
 <Content DataType="...Issue...">
  <TextBlock Text="{Binding Id}"></TextBlock>
 </Content>
 <Content DataType="...MileStone...">
  <TextBlock Text="{Binding DisplayText}"></TextBlock>
  <TextBlock Text="{Binding AnotherPropertyOfMileStone}"></TextBlock>
 </Content>
</StackPanel>

Thanks for your help! Markus