Avalonia How To Create Custom Popup - avaloniaui

Question

A little explanation first:
This is source code of Popup element
And this is example of using Popup DatePicker and it's xaml
I've tried use this example on empty window like this
Here is result:
So I want to create a OK/Cancel pick panel and use like DateTimePicker Pop and Select what do you want and accept or abort the selections.
How can I create a simple custom picker like this.

Answer 1

Edit: Here is My DateTimePicker and screenshots
After Tap
Ok I analyzed the existing codes for hours. Simply the answer is:
Step 1: Create a presenter class for manage your controls and events for popup. (like DatePickerPresenter
namespace AvaloniaTest.Views {
public class SabriPresenter : PickerPresenterBase
{
...
}
}
Step 2: Create Template for this presenter in your window or resource.
<Window xmlns="bla bla bla"
xmlns:v="using:AvaloniaTest.Views"
Title="AvaloniaTest">
<Design.DataContext>
<vm:MainWindowViewModel/>
</Design.DataContext>
<Window.Styles>
<Style Selector="v|SabriPresenter" >
<Setter Property="Template">
<ControlTemplate>
<Grid Background="AliceBlue">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100"/>
<ColumnDefinition Width="100"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="100"/>
<RowDefinition Height="20"/>
</Grid.RowDefinitions>
<Panel Grid.Column="0" Grid.Row="0" Grid.ColumnSpan="2">
<TextBlock Text="Your content..."/>
</Panel>
<Button Grid.Column="0" Grid.Row="0" Content="OK"/>
<Button Grid.Column="1" Grid.Row="0" Content="Cancel"/>
</Grid>
</ControlTemplate>
</Setter>
</Style>
</Window.Styles>
</Window>
Step 3: Use this presenter wherever you want
<Window xmlns="bla bla"
xmlns:v="using:AvaloniaTest.Views"
>
<StackPanel Orientation="Vertical" VerticalAlignment="Center">
<TextBlock Text="{Binding Greeting}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Button Content="Popeye" Name="sabri"/>
<Popup Name="Popup"
WindowManagerAddShadowHint="False"
StaysOpen="False"
PlacementMode="Bottom"
PlacementTarget="{Binding ElementName=sabri}"
>
<v:SabriPresenter />
</Popup>
</StackPanel>
</Window>
Ta-daa!