如何在 xamarin.forms 中获取 ListView 的子项？

Question

<ListView x:Name="ListNewsLetter"  AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1"  SeparatorVisibility="Default" VerticalOptions="Fill" ItemTapped="ListNewsLetter_ItemTapped" HasUnevenRows="True">
          <ListView.ItemTemplate>
            <DataTemplate>
              <ViewCell>
                <ViewCell.View>
                  <StackLayout HorizontalOptions="Fill" VerticalOptions="Center" Padding="5">
                    <StackLayout Padding="1" BackgroundColor="#f15a23" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
                      <StackLayout x:Name="stkNewsLetter" VerticalOptions="Center" BackgroundColor="#f15a23" Orientation="Horizontal" HeightRequest="30" Padding="6,0,6,0">
                        <Label x:Name="lblName" Text="{Binding NewsHeadline}" HorizontalOptions="StartAndExpand" TextColor="White" VerticalTextAlignment="Center" FontSize="Small"/>
                        <Image x:Name="imgPlus_Minus" HeightRequest="20" WidthRequest="20" Source="ico_down_arrow2_right.png" HorizontalOptions="End" ClassId="{Binding TapId}">
                          <Image.GestureRecognizers>
                            <TapGestureRecognizer Tapped="img_Tapped" NumberOfTapsRequired="1" />
                          </Image.GestureRecognizers>
                        </Image>
                      </StackLayout>
                      <StackLayout x:Name="stkNewsLetterDetail" Orientation="Vertical" BackgroundColor="#ffffff" IsVisible="true" HorizontalOptions="FillAndExpand" Padding="6,0,6,0">
                        <Label x:Name="lblDate" Text="{Binding NewsDate}" HorizontalOptions="StartAndExpand" VerticalTextAlignment="Start" TextColor="#585858" FontSize="Small"/>
                        <Label x:Name="lblDetail" Text="{Binding NewsDetails}" HorizontalOptions="FillAndExpand" VerticalTextAlignment="Start" TextColor="#585858" FontSize="Small"/>
                      </StackLayout>
                    </StackLayout>
                  </StackLayout>
                </ViewCell.View>
              </ViewCell>
            </DataTemplate>
          </ListView.ItemTemplate>
        </ListView>

As you see in code ListView having main two child named "stkNewsLetter" and "stkNewLetterDetail". First Stack having Image and I want to change visibility of second stack on Image tap event.

In windows phone It will possible to get UI elements of List view but In xamarin.forms how it is possible?

Answer 1

You should bind to the Visability property on the stackLayout in the same way you are binding the Text. If the stackLayout doesn't have a visibility property you may need to wrap it within another control that does.

The click should change a visibility property in you viewmodel which will get picked up by the binding mentioned above.

Answer 2

For those who came here to get the child elements through Name like me,here is the solution:

var selectedItem = //any item selected within listview through OnItemTapped
StackLayout child1 = selectedItem.FindByName<StackLayout>("stkNewsLetter");