具有HasUnEvenRows = True的Xamarin Forms ListView占用完整的屏幕

Question

我的屏幕上有ListView的不同视图。 ListView几乎填满了屏幕，ListView下面的元素不可见。我设置了HasUnEvenRows=True，因为每个列表项都有不同的高度。

<StackLayout Spacing="0">
<local:PageHeader></local:PageHeader>

<Grid Padding="25,15,25,10" Grid.RowSpacing="0">

  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="Auto"></ColumnDefinition>
    <ColumnDefinition Width="*"></ColumnDefinition>
    <ColumnDefinition Width="Auto"></ColumnDefinition>
  </Grid.ColumnDefinitions>

  <Grid.RowDefinitions>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
    <RowDefinition Height="Auto"></RowDefinition>
  </Grid.RowDefinitions>

  <Label Grid.Column="0" Grid.Row="0" VerticalOptions="CenterAndExpand" Grid.ColumnSpan="1" Text="{local:Translate FROM_COLON}" FontSize="18"></Label>

  <StackLayout Orientation="Vertical" Grid.Column="1" Grid.Row="0" Grid.RowSpan="3" Grid.ColumnSpan="3">
    <Label Text="{Binding Group}" TextColor="{x:Static local:ColorUtils.DarkBlue}" FontStyle="Bold" FontSize="18"></Label>
    <Label Text="{Binding Sender, StringFormat='&lt;{0}&gt;'}" TextColor="{x:Static local:ColorUtils.DarkBlue}" FontSize="18"></Label>
  </StackLayout>

  <ContentView  Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="3" Padding="0,15,0,0">
  <Button Text="{Binding DetailsButtonTitle}" Clicked="OnDetailButtonClick" BackgroundColor="Transparent" TextColor="{x:Static local:ColorUtils.DarkBlue}" HorizontalOptions="Start" VerticalOptions="StartAndExpand" Padding="0"></Button>
  </ContentView>
  <Button Grid.Column="3" Grid.Row="1" Grid.RowSpan="{Binding ReplyButtonRowSpan}" Text="{local:Translate REPLY}" Image="reply_arrow_small" BackgroundColor="Transparent" TextColor="{x:Static local:ColorUtils.Gray}" HorizontalOptions="End" VerticalOptions="EndAndExpand" Padding="0" FontSize="13" WidthRequest="65" Clicked="OnReplyButtonClick"></Button>


  <Label Grid.Column="0" Grid.Row="2" Grid.ColumnSpan="3" IsVisible="{Binding IsDetailShown, Converter={local:NotConverter Convert}}" Text="{Binding HumanizedDateFormat}" TextColor="{x:Static local:ColorUtils.Gray}"></Label>

  <ContentView Padding="0,0,0,5" Grid.Column="0" Grid.Row="2" IsVisible="{Binding IsDetailShown}" >
    <Label Text="{local:Translate FROM_COLON}" TextColor="{x:Static local:ColorUtils.Gray}" FontStyle="Bold" />
  </ContentView>
  <StackLayout Orientation="Horizontal" Grid.Column="1" Grid.Row="2" Grid.RowSpan="2" Grid.ColumnSpan="3" IsVisible="{Binding IsDetailShown}">
    <Label VerticalTextAlignment="Start" Text="{Binding Group}" TextColor="{x:Static local:ColorUtils.Gray}" FontStyle="Bold" />
    <Label VerticalTextAlignment="Start" Text="{Binding Sender, StringFormat='&lt;{0}&gt;'}" TextColor="{x:Static local:ColorUtils.Gray}"></Label>
  </StackLayout>

  <Label Grid.Column="0" Grid.Row="4" Grid.RowSpan="1" IsVisible="{Binding IsDetailShown}" Text="{local:Translate TO_COLON}" TextColor="{x:Static local:ColorUtils.Gray}" FontStyle="Bold" />
  <ListView x:Name="ListToAddresses" Grid.RowSpan="1" Grid.Column="1" Grid.Row="4" Grid.ColumnSpan="3" IsVisible="{Binding IsDetailShown}" HeightRequest="{Binding ListHeight}" VerticalOptions="Start" HasUnevenRows="True" CachingStrategy="RecycleElement" ItemsSource="{Binding Recipients}" SeparatorVisibility="None">
    <ListView.ItemTemplate>
      <DataTemplate>
        <ViewCell IsEnabled="False">
          <StackLayout VerticalOptions="Start" Padding="0,0,0,12" >
              <Label Text="{Binding Path=Key}" VerticalTextAlignment="Start" TextColor="{x:Static local:ColorUtils.Gray}" FontStyle="Bold" VerticalOptions="Start" />
              <Label Text="{Binding Path=Value}" VerticalTextAlignment="Start"  TextColor="{x:Static local:ColorUtils.Gray}" VerticalOptions="Start" />
          </StackLayout>
        </ViewCell>
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>

  <ContentView Padding="0,5,0,0" Grid.Column="0" Grid.Row="5" IsVisible="{Binding IsDetailShown}">
    <Label Text="{local:Translate DATE_COLON}" TextColor="{x:Static local:ColorUtils.Gray}"  FontStyle="Bold" />
  </ContentView>
  <Label Grid.Column="1" Grid.Row="5" Grid.ColumnSpan="3" VerticalTextAlignment="End" IsVisible="{Binding IsDetailShown}" Text="{Binding LongDateFormat}" TextColor="{x:Static local:ColorUtils.Gray}"></Label>
</Grid>
<BoxView HeightRequest="1" BackgroundColor="{x:Static local:ColorUtils.LightGray}"></BoxView>
<ContentView Padding="25,15,25,0">
  <Label Text="{Binding Description}" FontSize="18"></Label>
</ContentView>
</StackLayout>