XAML and namespace

Asknet · November 2016

Hi there,
I'm trying to create a CarouselPage in Xamarin.Forms using XAML.
This CarousePage is populated by an ItemSource.
The problem is that when I try to read a label.Text in CS from a XAML page, I've an error saying "the name 'xyz' does not exist in the current context".
I think it's caused by a namespace error but I don't know how to resolve it.

Can you help me?

This is the XAML code:

MainPage.xaml

<?xml version="1.0" encoding="UTF-8"?>
<CarouselPage 
        xmlns="http://xamarin.com/schemas/2014/forms" 
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
        xmlns:control="clr-namespace:Xamarin.Forms;assembly=Xamarin.Forms.CarouselView"
        x:Class="CarouselPageNavigation.MainPage">


    <CarouselPage.ItemTemplate>
        <DataTemplate>
            <ContentPage>
                <ContentPage.Padding>
                    <OnPlatform x:TypeArguments="Thickness" iOS="0,40,0,0" Android="10,0,10,0" />
                </ContentPage.Padding>
                <StackLayout>
                    <Label x:Name="lblName" Text="{Binding Name}" FontSize="Medium"   />
                </StackLayout>
            </ContentPage>
        </DataTemplate>
    </CarouselPage.ItemTemplate>
</CarouselPage>

and this is the code behind

MainPage.xaml.cs

using System;
using Xamarin.Forms;

namespace CarouselPageNavigation
{
    public partial class MainPage : CarouselPage
    {
        public MainPage()
        {
            InitializeComponent();
            ItemsSource = ProductsDataModel.All;
            lblName.Text = "test";  //  **<==  HERE THE ERROR**
        }
    }
}

PaulDiston · November 2016

You should set the Name property that your Label's Text binds to rather than trying to set the Label's Text property. As the Label is within an ItemTemplate it won't be accessible in the way you intend.

LJong · November 2016

Are you trying to parse the x:Name in the Binding place?

This is not how you define the text. The binding refers to a binding to the viewmodel or any other bindingcontext you have added to the page.

for example:

namespace BNApp.Views.DetailViews
{
    public partial class SettingsPage : BNPage
    {
        public SettingsPage()
        {
            InitializeComponent();
            BindingContext = new SettingsPageViewModel(this, this.Navigation, ListViewSettings);
        }
    }
}

I have set a BindingContext to a viewmodel which I wrote with certain data in it. I have for example bound my listview Itemsource

<?xml version="1.0" encoding="utf-8" ?>
<controls:BNPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:controls="clr-namespace:BNApp.Controls;assembly=BNApp"
             x:Class="BNApp.Views.DetailViews.SettingsPage">
  <AbsoluteLayout HorizontalOptions="FillAndExpand"
                  VerticalOptions="FillAndExpand">
    <StackLayout BackgroundColor="{StaticResource BackgroundColorMain}"
                 AbsoluteLayout.LayoutFlags="All"
                 AbsoluteLayout.LayoutBounds="0,0,1,1"
                 Margin="0">
      <StackLayout BackgroundColor="Transparent">
        <controls:BNListview x:Name="ListViewSettings"
                             ItemsSource="{Binding MenuList}"
                             BackgroundColor="Transparent"
                             SeparatorVisibility="None"
                             ItemClickCommand="{Binding SelectedItemCommand}" >
          <ListView.Header>
            <StackLayout Spacing="3">
              <controls:BNLabel TextId="Afspraken"
                                TextColor="{StaticResource SecundairColor}"
                                VerticalTextAlignment="Center"
                                FontAttributes="Bold"
                                FontSize="20"
                                Margin="15,0,0,0"/>
              <BoxView BackgroundColor="{StaticResource MainColor}"
                       HeightRequest="1"/>
            </StackLayout>
          </ListView.Header>
          <ListView.ItemTemplate>
            <DataTemplate>
              <ViewCell>
                <StackLayout Spacing="0">
                  <StackLayout Orientation="Horizontal"
                               VerticalOptions="FillAndExpand"
                               HorizontalOptions="FillAndExpand">
                    <controls:BNLabel Text="{Binding DisplayName}"
                                      VerticalTextAlignment="Center"
                                      TextColor="{StaticResource SecundairColor}"
                                      FontSize="16"
                                      Margin="15,0,0,0"/>
                    <Image Source="NextRight.png"
                           Aspect="AspectFill"
                           WidthRequest="24"
                           HeightRequest="24"
                           IsOpaque="True"
                           HorizontalOptions="EndAndExpand"
                           VerticalOptions="CenterAndExpand"/>
                  </StackLayout>
                  <BoxView  BackgroundColor="{StaticResource MainColor}"
                            HeightRequest="1"
                            VerticalOptions="End"/>
                </StackLayout>
              </ViewCell>
            </DataTemplate>
          </ListView.ItemTemplate>
        </controls:BNListview>
      </StackLayout>
    </StackLayout>
  </AbsoluteLayout>
</controls:BNPage>

I have declared a collection inside my SettingViewModelPage that is of name ''MenuList'' for example:

SettingsViewModelPage

  public ObservableCollection<SettingsMenuModel> MenuList
        {
            get { return _listMenu; }
            set
            {
                _listMenu = value;
                OnPropertyChanged("MenuList");
            }
        }

If I were you I should read up about DataBinding and MVVM. You can watch alot of youtube tutorials for explaining this.

Cheers,

Luuk

Asknet · November 2016

@PaulDiston how can I set the Name property that my Label's Text binds to. Can you give me an example?

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