How do we bind data to a `footer` in Xamarin Forms - xamarin

Question

How do we bind data to a footer inside ListView in Xamarin Forms, here I would need to pass the count_in value to footer.
<ListView x:Name="listView">
<ListView.Footer>
<StackLayout>
<Label Text="{Binding Count}" BackgroundColor="Gray"></Label>
</StackLayout>
</ListView.Footer>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
</Grid.ColumnDefinitions>
<Image Source="{Binding image}" WidthRequest="50" HeightRequest="50" Grid.Column="0" VerticalOptions="Center"/>
<StackLayout Grid.Column="1">
<Label Text="{Binding FullName}" TextColor="#f35e20" HorizontalTextAlignment="Center"/>
</StackLayout>
<StackLayout Grid.Column="2">
<Label Text="{Binding SoccerStatus}" HorizontalTextAlignment="Center" TextColor="#503026"/>
</StackLayout>
<StackLayout Grid.Column="3">
<Label Text="{Binding CurrentDate}" HorizontalTextAlignment="Center" TextColor="#503026"/>
</StackLayout>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Below is the DisplayCount() gets the count from database;
public void DisplayCount()
{
var datetoday = DateTime.Now.ToString("ddMMyyyy");
var count_in = (from x in conn.Table<SoccerAvailability>().Where(x => string.Equals(x.SoccerStatus, "IN", StringComparison.OrdinalIgnoreCase) && x.CurrentDate == datetoday) select x).Count();
}

Answer 1

you are binding to Count
<Label Text="{Binding Count}" BackgroundColor="Gray"></Label>
so Count needs to be a public property on your ViewModel
public int Count { get; set; }

Answer 2

Now getting database exception SQLite exception no such function
equals
This is because SQLLite linq doesn't recognize the string.Equals method. You could convert it to list using ToListAsync for one condition. Then filter the c# list object using equals:
var datetoday = DateTime.Now.ToString("ddMMyyyy");
var items = await conn.Table<SoccerAvailability>().Where(x => x.CurrentDate == datetoday).ToListAsync();
var finalsItems = items.Where(x => string.Equals(x.SoccerStatus, "IN", StringComparison.OrdinalIgnoreCase)).ToList();
Count = finalsItems.Count();
At last, binding your Lable's Text to this Count property.
Edit about binding:
Have you set your content page to your ViewModel? Moreover, implement the INotifyPropertyChanged interface in your view model:
// Set your page's binding context
BindingContext = new PageViewModel();
public class PageViewModel : INotifyPropertyChanged
{
int count;
public int Count
{
set
{
if (count != value)
{
count = value;
onPropertyChanged();
}
}
get
{
return count;
}
}
public event PropertyChangedEventHandler PropertyChanged;
void onPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Edit2:
If you didn't use view model, set a name to your footer label:
<ListView.Footer>
<StackLayout>
<Label x:Name="FooterLabel" BackgroundColor="Gray"></Label>
</StackLayout>
</ListView.Footer>
Then set its value directly:
//...
FooterLabel.Text = finalsItems.Count().ToString();

Answer 3

You need to specify the binding context for the footer.
By default for footers, headers, and templates in a list view, its binding context is going to be the item currently being displayed. So in this case Count would need to be a public property on the item from ItemsSource. Point the Count binding at your view model instead.
<Label Text="{Binding BindingContext.Count, Source={x:Reference xNameSetForCurrentPage}" BackgroundColor="Gray"></Label>
xNameSetForCurrentPage is the x:Name="name" set at the top most element(where all the xmlns stuff is) of the page.