Binded TappedCommand is not triggering-CodePudding

Can anyone point out why my Command is not triggering? This is my custom control

public partial class RateControl : Grid
    {
        public static readonly BindableProperty RateProperty = BindableProperty.Create(nameof(Rating), typeof(int), typeof(RateControl), 1, propertyChanged: OnRatePropertyChanged);

        private static void OnRatePropertyChanged(BindableObject bindable, object oldValue, object newValue)
        {
            if(bindable is RateControl && bindable != null && newValue is int)
            {
                (bindable as RateControl).OnRateClicked((int)newValue);
            }
        }

        public int Rating
        {
            set => SetValue(RateProperty, value);
            get => (int)GetValue(RateProperty);
        }

        public ICommand OnRateSelectedCommand { get; set; }

        public RateControl()
        {
            InitializeComponent();
            OnRateSelectedCommand = new Command<int>(OnRateClicked);
        }

        private void OnRateClicked(int rating)
        {
            Rating = rating;
            ChangeStar(Rating);
        }

        private void ChangeStar(int starcount)
        {
            for (int i = 1; i <= starcount; i  )
            {
                (FindByName($"star{i}") as Label).Text = RsrIcon.StarFull;
            }

            for (int i = starcount   1; i <= 5; i  )
            {
                (FindByName($"star{i}") as Label).Text = RsrIcon.StarEmpty;
            }
        }
    }

And this is my Xaml

<Grid xmlns="http://xamarin.com/schemas/2014/forms" 
      xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
      x:Class="Mobile.Controls.RateControl"
      xmlns:common="clr-namespace:Mobile.Common"
      xmlns:control="clr-namespace:Mobile.Controls"
      RowDefinitions="Auto"
      x:Name="component"
      ColumnDefinitions="30,30,30,30,30"
      ColumnSpacing="10">
    
    <control:TappableLabel FontSize="Large"
                           x:Name="star1"
                           TappedCommand="{x:Binding OnRateSelectedCommand, Source={x:Reference component}}"
                           TappedCommandParameter="1"
                           Text="{Static common:RsrIcon.StarEmpty}"
                           TextColor="{StaticResource RsrYellow}"
                           VerticalOptions="Center"/>

.....

So the TappableLabel is just a custom TappedGesture, The thing is upon clicking the RateControl either be StarFull or StarEmpty. The initialization of the command is working, but upon clicking nothing is happening.

CodePudding user response：

I've never seen {x:Binding ... used with Xamarin Forms.
Change it to {Binding ...:

... TappedCommand="{Binding OnRateSelectedCommand, Source={x:Reference component}}"

Optionally, add as last line in constructor:

    BindingContext = this;

Then you can do binding simply with {Binding OnRateSelectedCommand}:

... TappedCommand="{Binding OnRateSelectedCommand}"

CodePudding user response：

The generic type of Command should be string not int.

Modify your code as below

//xaml
TappedCommand="{Binding OnRateSelectedCommand}"

public RateControl()
{
   InitializeComponent();
   OnRateSelectedCommand = new Command<string>(OnRateClicked);
   BindingContext = this;
}

private void OnRateClicked(string rating)
{

}