Кнопка исчезает, когда я возвращаюсь к предыдущему экрану в iOS xamarin.fomrs

Question

Здравствуйте, я новичок в разработке приложений с помощью форм xamarin, у меня есть экран с тремя текстами редактирования, когда я щелкаю текст редактирования клиента, он открывает новый экран со списком элементов, когда я возвращаюсь или нажимаю элементкнопка на предыдущих экранах исчезает.

Вот URL-адреса изображения:

Здесь идеально подходят кнопки

экран списка элементов

Кнопка исчезает при нажатии элемента или назад

Вот полный код:

Это основной файл заказа на добавление

public class AddOrderPageModel : BaseEntryPageModel
    {
public AddOrderPageModel(OrderDataModel order, bool isEditable)
        {
            this.order = order;
            this.isEditable = isEditable;
        }
 public string Client
        {
            get
            {
                return this.client;
            }

            set
            {
                if (this.client != value)
                {
                    this.client = value;
                    this.OnPropertyChanged("Client");
                }
            }
        }
public ICommand SearchClientCommand
        {
            get
            {
                return new Command(this.OnSearchClientCommand);
            }
        }
private void OnSearchClientCommand(object obj)
        {
            refreshOrder = false;
            PartyListPageModel pageModel = new PartyListPageModel();
            pageModel.PartySelected = this.ClientSelected;
            NavigationHelper.PushOnMainNavigation(new PartyListPage(pageModel));
        }

} ​​

Вот класс модели списка участников:

public PartyListPage(PartyListPageModel model)
        {
            try
            {
                this.BindingContext = model;
                model.CurrentPage = this;
                this.InitializeComponent();

                this.Appearing += model.Init;
                this.ListView.ItemSelected += model.OnItemSelected;
                txtSearch.TextChanged += model.TxtSearch_TextChanged;
                SetTapGestureEventToSearchImage();
            }
            catch (Exception) { throw; }
        }

// And some methods

Страница списка участников xaml:

<?xml version="1.0" encoding="UTF-8"?>
<basepage:BasePage
    xmlns        ="http://xamarin.com/schemas/2014/forms"
    xmlns:x       ="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class       ="Biocorp.AppClasses.PagesAndViewModels.Party.PartyList.PartyListPage"
    xmlns:basepage="clr-namespace:Biocorp.AppClasses.PagesAndViewModels.Base;assembly=Biocorp"
    xmlns:i18n    ="clr-namespace:Biocorp;assembly=Biocorp"
    xmlns:rendered="clr-namespace:Biocorp.AppClasses.Rendered;assembly=Biocorp">
  <ContentPage.Content>
    <RelativeLayout
        HorizontalOptions="Fill"
        BackgroundColor  ="White">
      <RelativeLayout
          VerticalOptions  ="Fill"
          HorizontalOptions="Fill">
          <RelativeLayout.HeightRequest>
              <OnPlatform x:TypeArguments="x:Double">
                  <On Platform="Android">50</On>
                  <On Platform="iOS">100</On>
              </OnPlatform>
          </RelativeLayout.HeightRequest>
        <rendered:BaseButton
            IsEnabled                      ="false"
            Text                           =""
            BackgroundColor                ="White"
            BorderRadius                   ="2"
            BorderWidth                    ="1"
            RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=5}"
            RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=5}"
            RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-10}"
            RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-10}" />
        <StackLayout
            Orientation                    ="Horizontal"
            Spacing                        ="5"
            RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=5}"
            RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=5}"
            RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-10}"
            RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-10}">
          <StackLayout
              Orientation      ="Vertical"
              Spacing          ="0"
              Padding          ="0,0,0,0"
              VerticalOptions  ="Fill"
              HorizontalOptions="End"
              WidthRequest     ="40">
            <Image
                Source           ="ic_back"
                Aspect           ="AspectFit"
                WidthRequest     ="15"
                HeightRequest    ="15"
                VerticalOptions  ="CenterAndExpand"
                HorizontalOptions="CenterAndExpand" />
            <StackLayout.GestureRecognizers>
              <TapGestureRecognizer
                  Command="{Binding BackCommand}" />
            </StackLayout.GestureRecognizers>
          </StackLayout>
          <StackLayout
              Orientation      ="Vertical"
              Spacing          ="0"
              Padding          ="5,5,15,0"
              VerticalOptions  ="Fill"
              HorizontalOptions="FillAndExpand">
            <rendered:BaseEntry
                Text             ="{Binding SearchText}"
                x:Name           ="txtSearch"
                Placeholder      ="{i18n:Translate App_Search}"
                HorizontalOptions="FillAndExpand"
                VerticalOptions  ="FillAndExpand"
                HeightRequest    ="40"
                BackgroundColor  ="Transparent"
                FontSize         ="14"
                TextColor        ="Black"
                FontAttributes   ="None">
            </rendered:BaseEntry>
          </StackLayout>
          <StackLayout
              Orientation      ="Vertical"
              Spacing          ="0"
              Padding          ="0,0,0,0"
              VerticalOptions  ="Fill"
              HorizontalOptions="End"
              x:Name           ="slSearch"
              WidthRequest     ="40">
            <Image
                Source           ="ic_search_blue"
                Aspect           ="AspectFit"
                WidthRequest     ="15"
                HeightRequest    ="15"
                VerticalOptions  ="CenterAndExpand"
                HorizontalOptions="CenterAndExpand" />
          </StackLayout>
        </StackLayout>
      </RelativeLayout>
      <ListView
          x:Name                         ="listView"
          SeparatorVisibility            ="None"
          ItemsSource                    ="{Binding PartyList}"
          BackgroundColor                ="{StaticResource GrayLightBackground}"
          HasUnevenRows                  ="false"
          RowHeight                      ="74"
          VerticalOptions                ="FillAndExpand"
          RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=0}"
          RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=74}"
          RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=0}"
          RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-74}">
        <ListView.ItemTemplate>
          <DataTemplate>
            <ViewCell>
              <StackLayout
                  Orientation    ="Vertical" >
                <StackLayout
                    Orientation      ="Horizontal"
                    HorizontalOptions="FillAndExpand"
                    VerticalOptions  ="CenterAndExpand"
                    HeightRequest    ="52"
                    Padding          ="10"
                    BackgroundColor  ="White">

                  <StackLayout
                      Orientation      ="Vertical"
                      HorizontalOptions="StartAndExpand"
                      BackgroundColor  ="White">
                    <rendered:BaseLabel
                        Text             ="{Binding PartyName}"
                        HorizontalOptions="StartAndExpand"
                        VerticalOptions  ="Fill"
                        Style            ="{StaticResource RowStyle}" />
                    <StackLayout
                      Padding     ="0,5"
                      Orientation ="Horizontal">
                      <rendered:BaseLabel
                          Text             ="{i18n:Translate PartyList_PartyType}"
                          HorizontalOptions="Start"
                          VerticalOptions  ="Fill"
                          Style            ="{StaticResource RowStyle}" />
                      <rendered:BaseLabel
                          Text             ="{Binding PartyType}"
                          HorizontalOptions="Center"
                          VerticalOptions  ="Fill"
                          Style            ="{StaticResource RowStyle}" />
                    </StackLayout>

                  </StackLayout>
                  <rendered:BaseLabel
                      Text             ="{Binding LocationDescription}"
                      HorizontalOptions="End"
                      VerticalOptions  ="CenterAndExpand"
                      Style            ="{StaticResource RowStyle}" />

                </StackLayout>
              </StackLayout>
            </ViewCell>
          </DataTemplate>
        </ListView.ItemTemplate>
      </ListView>
    </RelativeLayout>
  </ContentPage.Content>
</basepage:BasePage>

Добавить страницу заказа xaml:

<?xml version="1.0" encoding="UTF-8"?>
<basepage:BasePage
    xmlns                         ="http://xamarin.com/schemas/2014/forms"
    xmlns:x                        ="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class                        ="Biocorp.AppClasses.PagesAndViewModels.Order.AddOrderPage"
    xmlns:basepage                 ="clr-namespace:Biocorp.AppClasses.PagesAndViewModels.Base;assembly=Biocorp"
    xmlns:i18n                     ="clr-namespace:Biocorp;assembly=Biocorp"
    xmlns:rendered                 ="clr-namespace:Biocorp.AppClasses.Rendered;assembly=Biocorp"
    NavigationPage.HasNavigationBar="true"
    Title                          ="{i18n:Translate AddOrder_Order}">
  <ContentPage.Content>
    <RelativeLayout
        HorizontalOptions="Fill">
      <ScrollView
          RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=0}"
          RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=0}"
          RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=0}"
          RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-53}">
        <StackLayout
            Orientation      ="Vertical"
            Spacing          ="0"
            Padding          ="0,7,0,7"
            VerticalOptions  ="Start"
            HorizontalOptions="Fill">
          <RelativeLayout
              HeightRequest    ="64"
              HorizontalOptions="Fill">
            <rendered:BaseButton
                IsEnabled                      ="false"
                Text                           =""
                BackgroundColor                ="{StaticResource GrayTextBackground}"
                BorderRadius                   ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}" />
            <StackLayout
                Orientation                    ="Horizontal"
                Spacing                        ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}">
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="15,5,15,5"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="FillAndExpand">
                <rendered:BaseLabel
                    Text                   ="{i18n:Translate AddOrder_Date}"
                    Style                  ="{StaticResource LabelStyle}">
                </rendered:BaseLabel>
                <rendered:BaseLabel
                    Text             ="{Binding Date}"
                    Style            ="{StaticResource TextboxStyle}" >
                </rendered:BaseLabel>
                  <StackLayout.GestureRecognizers>
                  <TapGestureRecognizer
                      Command="{Binding DateCommand}" />
                </StackLayout.GestureRecognizers>
              </StackLayout>
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="0,0,0,0"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="End"
                  WidthRequest     ="40">
                <Image
                    Source           ="ic_date"
                    Aspect           ="AspectFit"
                    WidthRequest     ="15"
                    HeightRequest    ="15"
                    VerticalOptions  ="CenterAndExpand"
                    HorizontalOptions="CenterAndExpand" />
              </StackLayout>
            </StackLayout>
          </RelativeLayout>
          <RelativeLayout
              HeightRequest    ="64"
              HorizontalOptions="Fill">
            <rendered:BaseButton
                IsEnabled                      ="false"
                Text                           =""
                BackgroundColor                ="{StaticResource GrayTextBackground}"
                BorderRadius                   ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}" />
            <StackLayout
                Orientation                    ="Horizontal"
                Spacing                        ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}">
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="15,5,15,5"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="FillAndExpand">
                <rendered:BaseLabel
                    Text                   ="{i18n:Translate AddOrder_Client}"
                    Style                  ="{StaticResource LabelStyle}">
                </rendered:BaseLabel>
                <rendered:BaseLabel
                    Text             ="{Binding Client}"
                    Style            ="{StaticResource TextboxStyle}">
                </rendered:BaseLabel>
                <StackLayout.GestureRecognizers>
                  <TapGestureRecognizer
                      Command="{Binding SearchClientCommand}" />
                </StackLayout.GestureRecognizers>
              </StackLayout>
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="0,0,0,0"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="End"
                  WidthRequest     ="40">
                <Image
                    Source           ="ic_client_name"
                    Aspect           ="AspectFit"
                    WidthRequest     ="15"
                    HeightRequest    ="15"
                    VerticalOptions  ="CenterAndExpand"
                    HorizontalOptions="CenterAndExpand" />
              </StackLayout>
            </StackLayout>
          </RelativeLayout>
          <RelativeLayout
              HeightRequest    ="64"
              HorizontalOptions="Fill">
            <rendered:BaseButton
                IsEnabled                      ="false"
                Text                           =""
                BackgroundColor                ="{StaticResource GrayTextBackground}"
                BorderRadius                   ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}" />
            <StackLayout
                Orientation                    ="Horizontal"
                Spacing                        ="5"
                RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=14}"
                RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=7}"
                RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=-28}"
                RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-14}">
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="15,5,15,5"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="FillAndExpand">
                <rendered:BaseLabel
                    Text                   ="{i18n:Translate AddOrder_Remarks}"
                    Style                  ="{StaticResource LabelStyle}" >
                </rendered:BaseLabel>
                <rendered:BorderlessEntry
                    Text             ="{Binding Remarks}"
                    Style            ="{StaticResource TextboxStyle}" >
                </rendered:BorderlessEntry>
              </StackLayout>
              <StackLayout
                  Orientation      ="Vertical"
                  Spacing          ="0"
                  Padding          ="0,0,0,0"
                  VerticalOptions  ="Fill"
                  HorizontalOptions="End"
                  WidthRequest     ="40">
                <Image
                    Source           ="ic_your_remarks"
                    Aspect           ="AspectFit"
                    WidthRequest     ="15"
                    HeightRequest    ="15"
                    VerticalOptions  ="CenterAndExpand"
                    HorizontalOptions="CenterAndExpand" />
              </StackLayout>
            </StackLayout>
            <RelativeLayout.GestureRecognizers>
              <TapGestureRecognizer
                  Tapped         ="OnTapGestureRecognizerForFocus" />
            </RelativeLayout.GestureRecognizers>
          </RelativeLayout>
        </StackLayout>
      </ScrollView>
      <RelativeLayout
          RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0, Constant=0}"
          RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-53}"
          RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1, Constant=0}"
          RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=53}">
        <rendered:BaseButton
            x:Name                         ="cancelButton"
            Command                        ="{Binding CancelCommand}"
            CommandParameter               ="{x:Reference cancelButton}"
            Text                           ="{i18n:Translate App_Cancel}"
            FontSize                       ="14"
            TextColor                      ="White"
            BackgroundColor                ="{StaticResource BlueDark_073B74}"
            FontAttributes                 ="Bold"
            BorderRadius                   ="5"
            RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.022, Constant=0}"
            RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=6}"
            RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.467, Constant=0}"
            RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-13}" />
        <rendered:BaseButton
            x:Name                         ="saveButton"
            Command                        ="{Binding ProceedCommand}"
            CommandParameter               ="{x:Reference saveButton}"
            Text                           ="{i18n:Translate App_Proceed}"
            FontSize                       ="14"
            TextColor                      ="{StaticResource BlueDark_073B74}"
            BackgroundColor                ="{StaticResource Golden_F5AF01}"
            FontAttributes                 ="Bold"
            BorderRadius                   ="5"
            RelativeLayout.XConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.511, Constant=0}"
            RelativeLayout.YConstraint     ="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0, Constant=6}"
            RelativeLayout.WidthConstraint ="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.467, Constant=0}"
            RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1, Constant=-13}" />
      </RelativeLayout>
    </RelativeLayout>
  </ContentPage.Content>
</basepage:BasePage>

Я также хотел бы добавить, что эта проблема только в iOS для Android, она работает отлично.Пожалуйста, проверьте и дайте мне знать, что мне не хватает, так как я новичок в xamarin.