How to create bindable command for custom component in Xamarin.Forms?

user_1694159 0
Viewed 950

I've a custom component where I've button and I'm trying to create a bindable command so that I can perform action based on viewmodel. I've tried few things but nothing seems to be working :

public static readonly BindableProperty CommandProperty = 
    BindableProperty.Create(nameof(Command), typeof(ICommand), typeof(MySample), null);

public ICommand Command
{
    get { return (ICommand)GetValue(CommandProperty); }
    set { SetValue(CommandProperty, value); }
}

// Helper method for invoking commands safely
public static void Execute(ICommand command)
{
    if (command == null) return;
    if (command.CanExecute(null))
    {
        command.Execute(null);
    }
}
xamarin.forms xamarin c#
3 Answers

You need to implement propertychanged for bindable property to enable binding.

public static readonly BindableProperty CommandProperty = 
    BindableProperty.Create(nameof(Command), typeof(Xamarin.Forms.Command), typeof(MySample), null, propertychanged: OnCommandPropertyChanged);

stativ void OnCommandPropertyChanged  (BindableObject bindable, object oldValue, object newValue)
{
    (bindable as MySample).Command = (Command)newValue;
}
user_79075910

You need to use TapGestureRecognizer to trigger Command:

public partial class View1 : ContentView
{
    public View1()
    {
        InitializeComponent();

        var gestureRecognizer = new TapGestureRecognizer();

        gestureRecognizer.Tapped += (s, e) => {
            if (Command != null && Command.CanExecute(null))
            {
                Command.Execute(null);
            }
        };

        this.GestureRecognizers.Add(gestureRecognizer);
    }
    // BindableProperty implementation
    public static readonly BindableProperty CommandProperty =
        BindableProperty.Create(nameof(Command), typeof(ICommand), typeof(View1), null);

    public ICommand Command
    {
        get { return (ICommand)GetValue(CommandProperty); }
        set { SetValue(CommandProperty, value); }
    }

    // Helper method for invoking commands safely
    public static void Execute(ICommand command)
    {
        if (command == null) return;
        if (command.CanExecute(null))
        {
            command.Execute(null);
        }
    }
}

I uploaded a sample project here and feel free to ask me any question.

user_105394460 

public ICommand MyCommand
        {
            get => (ICommand)GetValue(MyCommandProperty);
            set => SetValue(MyCommandProperty, value);
        }

        public static BindableProperty MyCommandProperty = BindableProperty.Create(
                                                 propertyName: "Command",
                                                 returnType: typeof(ICommand),
                                                 declaringType: typeof(View1),
                                                 defaultValue: null,
                                                 defaultBindingMode: BindingMode.TwoWay,
                                                 propertyChanged: MyCommandPropertyChanged);

        public static void MyCommandPropertyChanged(BindableObject bindable, object oldValue, object newValue)
        {
            var control = (CustomSignInTemplate)bindable;
            control.tempbtn.Command = (ICommand)newValue;
        }

user_16941590
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