layout.xaml

<Grid ColumnDefinitions="*,*" RowDefinitions="*,Auto">

  <Button Text="Abort" 
    Grid.Column="0"
    Grid.Row="1"
    BackgroundColor="Blue"
    TextColor="White"
    Margin="10, 0, 5, 15"
    CornerRadius="4" />
  <Button Text="OK" 
    Grid.Column="1"
    Grid.Row="1"
    Margin="5,0,10,15"
    BackgroundColor="Blue"
    TextColor="White"
    CornerRadius="4" />

  <ListView 
    Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="0" Grid.RowSpan="2"
    CachingStrategy="RecycleElement"
    VerticalOptions="FillAndExpand">
    <ListView.Header>
      <Grid RowDefinitions="Auto, Auto" Padding="10, 15">
        <Label Grid.Row="0" Text="This is the display text" HorizontalTextAlignment="Center" />
        <SearchBar Placeholder="Search" 
          Grid.Row="1"
          PlaceholderColor="Gray"
          Text=""
          TextColor="Black"
          BackgroundColor="LightGray"
          HeightRequest="40">
        </SearchBar>
      </Grid>
    </ListView.Header>
    <ListView.ItemsSource>
      <x:Array Type="{x:Type x:String}">
        <x:String>One</x:String>
        <x:String>Two</x:String>
        <x:String>Three</x:String>
        <x:String>Four</x:String>
        <x:String>Five</x:String>
        <x:String>Six</x:String>
        <x:String>Seven</x:String>
        <x:String>Eight</x:String>
        <x:String>Nine</x:String>
        <x:String>Ten</x:String>
        <x:String>Eleven</x:String>
        <x:String>Twelve</x:String>
        <x:String>Thirteen</x:String>
        <x:String>Fourteen</x:String>
        <x:String>Fifteen</x:String>
        <x:String>Sixteen</x:String>
        <x:String>Seventeen</x:String>
        <x:String>Eighteen</x:String>
        <x:String>Nineteen</x:String>
        <x:String>Twenty</x:String>
        <x:String>Twentyone</x:String>
        <x:String>Twentytwo</x:String>
        <x:String>Twentythree</x:String>
        <x:String>Twentyfour</x:String>
        <x:String>Twentyfive</x:String>
      </x:Array>
    </ListView.ItemsSource>
    <ListView.ItemTemplate>
      <DataTemplate>
        <ViewCell>
          <Label Text="{Binding .}" VerticalTextAlignment="Center" Margin="10" />
        </ViewCell>
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>
</Grid>