将重新绑定列表视图页面UI绑定后空白

Question

当我尝试重新绑定Listview UI时，空白意味着没有显示页面。这个问题只发生在我在iOS上测试我的项目时，在android中它运行得很好。我的代码页是一个文本完成事件，当我第一次运行我的代码时，UI看起来很完美。但是当我在文本框中写入一些文本并按下输入按钮UI隐藏在屏幕上并且屏幕上没有显示任何内容。

我的页面XAML与.cs页面可以从Google Drive下载我的代码部分如下： -

 <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">
                <Label FontSize="Medium" TextColor="#707070" Text="{Binding OrderNum}" 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>

绑定列表视图： -

 async void Txtentry_Completed(object sender, EventArgs e)
    {
        try
        {
           string s = ((Entry)sender).Text;
            if(s.Trim() != string.Empty)
            {
               BindListview(orderID);
            }

        }
        catch
        {
        }
    }

public void BindListview(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);
        }
    }


public List<GenericFields> GetDeliveryOrderItems(int _OrderID)
    {
        //DateTime dat = DateTime.Now.Date;
        //long tick = dat.Ticks;
        List<GenericFields> GN = new List<GenericFields>();
        try
        {
            GN = App.DAUtil.GetInboundOrderItems(_OrderID);

            if (GN.Count > 0)
            {
                bool _chkStatus = true;
                for (int i = 0; i < GN.Count(); i++)
                {
                    // if (GN[i].Inboundprocessed == "1")
                    if (Convert.ToString(GN[i].GFIELD6) != "")
                    {
                        GN[i].ImageStatus = "ok1.png";
                        GN[i].RowColour = "#D3D3D3";
                    }
                    else
                    {
                        GN[i].ImageStatus = "cancel1.png";
                        GN[i].RowColour = "#ffffff";
                        _chkStatus = false;
                    }
                }

            }
        }
        catch (Exception ex)
        {
            error(ex.Message, Convert.ToString(ex.InnerException), ex.Source, ex.StackTrace);
        }
        //
        return GN;
    }