在xamarin.forms xaml中刷新GridView

我有一个GridView，每个磁贴包含用户特定的详细信息，因此如果用户的详细信息在使用应用程序时必须更改，我希望刷新此视图 . 我已经尝试了以下方法，为我的一个瓷砖添加刷新，但这不起作用 . 有没有其他方法可以实现整个gridView？

Xaml

<Grid x:Name="cardBalance" >
            <Image Source="GiftCard.jpg" HorizontalOptions="Fill" VerticalOptions="Fill" Aspect="AspectFill" Grid.Row="0" Grid.Column="0" x:Name="CardImage"/>
            <Image Source="store2.jpg" HorizontalOptions="Fill" VerticalOptions="Fill" Aspect="AspectFill" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2"/>
            <Image Source="GridTrans.jpg" HorizontalOptions="Fill" VerticalOptions="Fill" Aspect="AspectFill" Grid.Row="0" Grid.Column="1" />
            <Image Source="ProfileBg2.JPG" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Aspect="AspectFill" Grid.Row="2" Grid.Column="0" />
            <Image Source="gridSettings.JPG" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Aspect="AspectFill" Grid.Row="2" Grid.Column="1" />

        <ScrollView Grid.Row="0" Grid.Column="0">
            <ListView x:Name="CardBalance" HasUnevenRows="True" Grid.Row="0" Grid.Column="0" VerticalOptions="Fill" IsPullToRefreshEnabled="True" Refreshing="CardBalance_Refreshing">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <StackLayout Orientation="Vertical"
                                 HorizontalOptions="FillAndExpand"
                                 VerticalOptions="FillAndExpand"
                                 x:Name="Layout">
                                <Frame>

                                    <StackLayout Orientation="Horizontal"  HorizontalOptions="FillAndExpand">
                                        <StackLayout Orientation="Vertical"  HorizontalOptions="FillAndExpand">
                                            <Label Text="Card Balance:" TextColor="Black"/>
                                            <Label Text="{Binding Balance}" TextColor="Black"/>
                                        </StackLayout>
                                        <StackLayout Orientation="Vertical"  HorizontalOptions="EndAndExpand">
                                            <Image Source="{Binding CustomerLogo}" HeightRequest="60" WidthRequest="60"></Image>
                                        </StackLayout>
                                    </StackLayout>
                                </Frame>
                            </StackLayout>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </ScrollView>

        <Label Text=" Tap to view detail" TextColor="Gainsboro" FontSize="14"  FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="0" Grid.Column="0" x:Name="CardTile"/>
        <Label Text=" Tap to view all card balances" TextColor="#64676b" FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="0" Grid.Column="0" x:Name="MultipleCards"/>


        <Label Text=" Transactions" TextColor="White" FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="0" Grid.Column="1"  x:Name="TransactionTile"/>
        <Label Text=" Promotions" TextColor="White" FontSize="30" FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="1" Grid.Column="0"  Grid.ColumnSpan="2"  x:Name="PromoTile"/>
        <Label Text=" My Profile" TextColor="White" FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="2" Grid.Column="0"  x:Name="ProfileTile" />
        <Label Text=" Settings" TextColor="White" FontAttributes="Bold" HorizontalTextAlignment="Start" VerticalTextAlignment="End" Grid.Row="2" Grid.Column="1"   x:Name="SettingsTile"/>

        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="2*" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="2*" />
            <ColumnDefinition Width="1*" />
        </Grid.ColumnDefinitions>
    </Grid>

Xaml.cs

public async void LoadCards()
    {
        try
        {
            List<Requests.Cards> cd = new List<Requests.Cards>();
            var content = "";
            HttpClient client = new HttpClient();
            var RestUrl = Settings.RestUrl + "/api/Customer/GetCustomerCards?CustomerID=" + Helpers.Settings.storecustID;
            client.BaseAddress = new Uri(RestUrl);
            client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
            client.DefaultRequestHeaders.Add("X-Giftworx-App", Helpers.Settings.Usertoken);
            HttpResponseMessage response = await client.GetAsync(RestUrl);

            content = await response.Content.ReadAsStringAsync();

            var Items = JsonConvert.DeserializeObject<List<Requests.Cards>>(content);

            CardBalance.ItemsSource = Items;
            TapGestureRecognizer cardsLabel = new TapGestureRecognizer();
                cardsLabel.Tapped += (sender, e) =>
                {
                    Navigation.PushAsync(new Cards());

                };

                CardTile.GestureRecognizers.Add(cardsLabel);         
        }
        catch (Exception ex)
        {
            string exception = ex.Message;
        }
    }

    private void CardBalance_Refreshing(object sender, EventArgs e)
    {
        LoadCards();
        CardBalance.IsRefreshing = false;          
    }