After press on return button the listview hide from UI IOS

After press the return button on screen keyboard the listview hide from screen.

<ListView x:Name="listViewOrder" ItemTapped="OnActivitySelected" HasUnevenRows="True">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                          <Frame   HasShadow="True" OutlineColor="Silver"   Padding="3">
                            <Grid BackgroundColor="{Binding RowColour}" ColumnSpacing="2" Padding="2">
                                <StackLayout Orientation="Horizontal" HeightRequest="35" BackgroundColor="{Binding RowColour}" Padding="10">
                                    <StackLayout Spacing="0" BackgroundColor="{Binding RowColour}" Orientation="Horizontal" HorizontalOptions="Start">
                                        <Label FontSize="Medium" TextColor="#707070" Text="{Binding GFIELD3}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"/>
                                    </StackLayout>

                                    <StackLayout Spacing="0" BackgroundColor="{Binding RowColour}" Orientation="Horizontal" HorizontalOptions="EndAndExpand">
                                        <Image Aspect="AspectFit" Source = "{Binding ImageStatus}" HorizontalOptions="StartAndExpand" VerticalOptions="Center" HeightRequest = "20" WidthRequest="20" />
                                    </StackLayout>
                                </StackLayout>
                            </Grid>
                          </Frame>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>

Code part

async void Txtentry_Completed(object sender, EventArgs e)
{
BiendListview(orderID);
}

 public void BiendListview(int OID)
        {
            try
            {
                List<GenericFields> GN = new List<GenericFields>();
                GN = GetDeliveryOrderItems(OID);
                if (GN != null)
                {
                   // listViewOrder.BeginRefresh();
                    listViewOrder.ItemsSource = GN;
                   // listViewOrder.EndRefresh();
                }
            }
            catch (Exception ex)
            {
                error(ex.Message, Convert.ToString(ex.InnerException), ex.Source, ex.StackTrace);
            }
        }