How to make a local ContentView bind a Label text - xamarin

Question

I made a ContentView with an Expander. I want to duplicate this Xaml code multiple times in an other Xaml file. But I want for each Expander a different Binding.
I linked this code (ContentView code):
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:expandable="clr-namespace:Expandable;assembly=ExpandableView"
x:Class="Hello.ExpandableView">
<ContentView.Content>
<expandable:ExpandableView Padding="5">
<expandable:ExpandableView.PrimaryView>
<Frame BackgroundColor="White" Padding="5" CornerRadius="10">
<StackLayout Orientation="Horizontal">
<Label x:Name="label" FontSize="16" TextColor="Black" FontAttributes="Bold" Padding="5" HorizontalTextAlignment="Start" HorizontalOptions="StartAndExpand"/>
<Image Source="arrow.png" WidthRequest="25" HeightRequest="25" Margin="5"/>
</StackLayout>
</Frame>
</expandable:ExpandableView.PrimaryView>
<expandable:ExpandableView.SecondaryViewTemplate>
<DataTemplate>
<Frame BackgroundColor="White" Padding="5" CornerRadius="10">
<Label Text="{Binding Tip1Uitleg}" FontSize="15" TextColor="Black" Padding="5"/>
</Frame>
</DataTemplate>
</expandable:ExpandableView.SecondaryViewTemplate>
</expandable:ExpandableView>
</ContentView.Content>
</ContentView>
namespace Hello
{
public partial class ExpandableView : ContentView
{
public static BindableProperty LabelProperty =
BindableProperty.Create(nameof(Label),
typeof(string),
typeof(ExpandableView),
propertyChanged: (b, o, n) => (b as ExpandableView).OnLabelChanged());
private void OnLabelChanged()
{
label.Text = Label; //label is the x:Name of your Label control in ExpandableView.xaml
}
public string Label
{
get => (string)GetValue(LabelProperty);
set => SetValue(LabelProperty, value);
}
}
}
To this code:
This works:
<local:ExpandableView Label="Hello"/>
But I want this. This does not work:
<?xml version="1.0" encoding="UTF-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:expandable="clr-namespace:Expandable;assembly=ExpandableView"
xmlns:local="clr-namespace:Hello"
x:Class="Hello.Health.HealthDetail"
Title="{Binding Name}">
<ContentPage.Content>
<ScrollView>
<StackLayout>
<Image Source="{Binding Image}"/>
<Label Text="{Binding Tip1Uitleg}" FontSize="15" TextColor="Black" Padding="10, 5, 10, 5"/>
<local:ExpandableView Label="{Binding Tip1}"/> //This is what it is all about
</StackLayout>
</ScrollView>
</ContentPage.Content>
</ContentPage>
CodeBehind:
namespace Hello.Health
{
public partial class HealthDetail : ContentPage
{
public HealthDetail(HealthStrings healthStrings)
{
if (healthStrings == null)
throw new ArgumentNullException();
BindingContext = healthStrings;
InitializeComponent();
}
}
}
How do I make this work? I have to make this above more dynamic, but I do not know how.
BTW This also works:
<Label Text="{Binding Tip1}" />
I am sorry for the unclear explanation, I hope someone can help me.
Thank you for your time :)

Answer 1

You should not bind to 'this' since you are using a BindableProperty. Instead you should update the Label.Text property when the value of the BindableProperty changes.
public static BindableProperty LabelProperty =
BindableProperty.Create(nameof(Label),
typeof(string),
typeof(ExpandableView),
propertyChanged:(b, o, n) => (b as ExpandableView).OnLabelChanged());
private void OnLabelChanged()
{
label.Text = Label; //label is the x:Name of your Label control in ExpandableView.xaml
}
public string Label
{
get => (string)GetValue(LabelProperty);
set => SetValue(LabelProperty, value);
}
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="YourProject.ExpandableView">
<Grid>
<Label x:Name="label"/>
</Grid>
</ContentView>

Answer 2

Normally, when you want to binding a value for binableproperty, you could try the code below:
ExpandableView: I make a simple contentview with the same binableproperty for you reference.
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XamarinDemo.Pages.ExpandableView">
<ContentView.Content>
<StackLayout>
<Label Text="Hello"></Label>
<Label x:Name="label"></Label>
</StackLayout>
</ContentView.Content>
</ContentView>
Code behind:
public partial class ExpandableView : ContentView
{
public static BindableProperty LabelProperty =
BindableProperty.Create(nameof(Label),
typeof(string),
typeof(ExpandableView),
propertyChanged: (b, o, n) => (b as
ExpandableView).OnLabelChanged());
private void OnLabelChanged()
{
label.Text = Label; //label is the x:Name of your Label control in ExpandableView.xaml
}
public string Label
{
get => (string)GetValue(LabelProperty);
set => SetValue(LabelProperty, value);
}
public ExpandableView()
{
InitializeComponent();
}
}
Usage:
<ContentPage.Content>
<local:ExpandableView Label="{Binding str}"></local:ExpandableView>
</ContentPage.Content>
Code Behind:
public partial class Page1 : ContentPage
{
public string str { get; set; }
public Page1()
{
InitializeComponent();
str = "okay";
this.BindingContext = this;
}
}