At a time only one expander expand on xamarin form - xamarin

Question

On my page there is a 4 expander ,I want to write a code for at a time one expander is expand ,What can I do for this scenario please help me ,For more clarifications I have a add image of expanders ,In this given code there is a one expander show ,but this type of a 4 expander available on my page and i want to expand one at a time
enter image description here
<StackLayout IsVisible="{Binding Synonyms,Converter={x:StaticResource CorrectionTypeVisiableConverter}}" Orientation="Vertical" VerticalOptions="StartAndExpand" HorizontalOptions="FillAndExpand">
<xct:Expander ExpandAnimationEasing="CubicIn"
ExpandAnimationLength="500"
CollapseAnimationEasing="CubicOut"
CollapseAnimationLength="500">
<xct:Expander.Header>
<Frame HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BorderColor="#F0F0F0" HasShadow="False" >
<StackLayout Orientation="Horizontal" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
<xct:BadgeView Text="{Binding Synonyms,Converter={StaticResource CorrectionCountBadgeConverter}}" BackgroundColor="#FADBD8" BadgePosition="TopLeft" TextColor="#E74C3C" HorizontalOptions="Start" FontSize="16" AutoHide="True" VerticalOptions="CenterAndExpand">
<Label Text=""></Label>
</xct:BadgeView>
<Label Text="{x:Static resources:AppResources.Synonyms}"
FontAttributes="Bold" VerticalOptions="CenterAndExpand"
FontSize="Medium" Style="{StaticResource MenueLableStyle}" HorizontalOptions="StartAndExpand" />
<Image Source="Expand.png"
HorizontalOptions="EndAndExpand"
VerticalOptions="CenterAndExpand">
<Image.Triggers>
<DataTrigger TargetType="Image"
Binding="{Binding Source={RelativeSource AncestorType={x:Type xct:Expander}}, Path=IsExpanded,Mode=OneTime}"
Value="True">
<Setter Property="Source"
Value="collapse.png" />
</DataTrigger>
</Image.Triggers>
</Image>
</StackLayout>
</Frame>
</xct:Expander.Header>
<xct:Expander.ContentTemplate>
<DataTemplate>
<StackLayout BindableLayout.ItemsSource="{Binding Synonyms}" VerticalOptions="StartAndExpand" HorizontalOptions="FillAndExpand">
<BindableLayout.ItemTemplate>
<DataTemplate>
<Frame HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BorderColor="#F0F0F0" HasShadow="False" >
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<StackLayout Grid.Row="0" Orientation="Horizontal">
<Label Text="{Binding s}" HorizontalOptions="Start" VerticalOptions="Center">
</Label>
<Label Text="--->" HorizontalOptions="Start" VerticalOptions="Center"></Label>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
</Grid.ColumnDefinitions>
<xct:BadgeView Grid.Column="0" Text="" BackgroundColor="#FADBD8" BadgePosition="TopRight" TextColor="#E74C3C" FontSize="14" HorizontalOptions="CenterAndExpand" AutoHide="True" VerticalOptions="Center" Background="#FADBD8" WidthRequest="80" HeightRequest="25">
<Label Text="{Binding c}"></Label>
</xct:BadgeView>
<ImageButton Grid.Column="0" Source="Storyedit.png"
HorizontalOptions="EndAndExpand" VerticalOptions="Center" WidthRequest="12" HeightRequest="12"/>
</Grid>
<ImageButton Source="Info.png" Command="{Binding Path=BindingContext.CorrectionInfoCommand,Source={x:Reference Name=storyView}}"
CommandParameter="{Binding .}" HorizontalOptions="EndAndExpand"/>
</StackLayout>
<Button Grid.Row="1" Text="{x:Static resources:AppResources.IgnoreButton}" Style="{StaticResource CancelButton}" VerticalOptions="EndAndExpand" HorizontalOptions="CenterAndExpand" ></Button>
<Button Grid.Row="1" Text="{x:Static resources:AppResources.AcceptButton}" Style="{StaticResource AcceptButton}" VerticalOptions="EndAndExpand" HorizontalOptions="StartAndExpand" ></Button>
<FlexLayout IsVisible="False" Grid.Row="3" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" AlignItems="Start" AlignContent="Center" Direction="Row" Wrap="Wrap" JustifyContent="Center">
<Button Text="{x:Static resources:AppResources.IgnoreButton}" Padding="5" Style="{StaticResource CancelButton}" HorizontalOptions="StartAndExpand"></Button>
<Button Text="{x:Static resources:AppResources.IgnoreAllButton}" Style="{StaticResource CancelButton}" HorizontalOptions="CenterAndExpand" Padding="5"></Button>
<Button Text="{x:Static resources:AppResources.AcceptButton}" Style="{StaticResource AcceptButton}" HorizontalOptions="StartAndExpand" Padding="5"></Button>
<Button Text="{x:Static resources:AppResources.AcceptAllButton}" Style="{StaticResource AcceptButton}" HorizontalOptions="CenterAndExpand" Padding="5"></Button>
</FlexLayout>
</Grid>
</Frame>
</DataTemplate>
</BindableLayout.ItemTemplate>
</StackLayout>
</DataTemplate>
</xct:Expander.ContentTemplate>
</xct:Expander>
</StackLayout>

Answer 1

You could binding true or false for the IsExpanded property to indicate that the Expander is expanded or collapsed.
I make a simple example for your reference.
Model:
public class Model : INotifyPropertyChanged
{
#region fields
public string _synonyms;
public string _s;
public bool _isexpand;
#endregion
public string Synonyms
{
get { return _synonyms; }
set { _synonyms = value; OnPropertyChanged("Synonyms"); }
}
public string s
{
get { return _s; }
set { _s = value; OnPropertyChanged("s"); }
}
public bool ISexpand
{
get { return _isexpand; }
set { _isexpand = value; OnPropertyChanged("ISexpand"); }
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
ViewModel:
public class ViewModel1
{
public ObservableCollection<Model> models { get; set; }
public ViewModel1()
{
CreateCollection();
}
public void CreateCollection()
{
models = new ObservableCollection<Model>()
{
new Model(){ Synonyms="Synonym1", s="A", ISexpand=false},
new Model(){ Synonyms="Synonym2", s="B",ISexpand=false},
new Model(){ Synonyms="Synonym3", s="C",ISexpand=false},
new Model(){ Synonyms="Synonym4", s="D",ISexpand=false},
new Model(){ Synonyms="Synonym5", s="E",ISexpand=false},
};
}
}
Xaml:
<ContentPage.BindingContext>
<local:ViewModel1></local:ViewModel1>
</ContentPage.BindingContext>
<ContentPage.Content>
<StackLayout x:Name="stacklayout" BindableLayout.ItemsSource="{Binding models}" Orientation="Vertical" VerticalOptions="StartAndExpand" HorizontalOptions="FillAndExpand">
<BindableLayout.ItemTemplate>
<DataTemplate>
<xct:Expander IsExpanded="{Binding ISexpand}" Tapped="Expander_Tapped" >
<xct:Expander.Header>
<Label Text="{Binding Synonyms}"></Label>
</xct:Expander.Header>
<xct:Expander.ContentTemplate>
<DataTemplate>
<Label Text="{Binding s}"></Label>
</DataTemplate>
</xct:Expander.ContentTemplate>
</xct:Expander>
</DataTemplate>
</BindableLayout.ItemTemplate>
</StackLayout>
</ContentPage.Content>
Code behind:
public partial class Page10 : ContentPage
{
ViewModel1 viewModel1=new ViewModel1();
public Page10()
{
InitializeComponent();
}
int i = 0;
private void Expander_Tapped(object sender, EventArgs e)
{
var expander = sender as Expander;
var label = expander.Header as Label;
var list = viewModel1.models;
foreach (var item in viewModel1.models)
{
if (item.Synonyms == label.Text)
{
item.ISexpand = true;
if (i >= 1)
{
foreach (var item1 in viewModel1.models.ToList())
{
if (item1.Synonyms!= label.Text)
{
item1.ISexpand = false;
}
}
BindableLayout.SetItemsSource(stacklayout, viewModel1.models);
}
}
}
i++;
}
}
OutPut:
https://imgur.com/4D6x1yB