c# - Xamarin 中的 TapGesture From Bound 属性

Question

好的，我有一个绑定(bind)到 viewModel 的 ViewCell 类。如果我创建一个标签，我可以这样做:

        var taskName = new Label()
        {
            XAlign = TextAlignment.Start,
            YAlign = TextAlignment.Start,
            FontSize = Device.GetNamedSize(NamedSize.Medium, typeof(Label)),
            FontAttributes = FontAttributes.Bold,
            LineBreakMode = LineBreakMode.TailTruncation
        };

        taskName.SetBinding(Label.TextProperty, "CompanyName");

我想做的是将对象的值绑定(bind)到 tapGesture。

        var tapGesturePhone = new TapGestureRecognizer ();

        var phoneIcon = new Image {
            HorizontalOptions = LayoutOptions.Center,
            VerticalOptions = LayoutOptions.Center,
            Source = "phone.png"

        };

        phoneIcon.GestureRecognizers.Add (tapGesturePhone);

        tapGesturePhone.Tapped += (sender, e) => {
            var uri = new Uri("tel:" + );
            Device.OpenUri(uri);

        };

        //uri.setbinding("Uri.text", "PhoneNo")?

关于如何执行此操作的任何想法？解决办法也可以。

我有一个名为 ProjectContacts 的模型，其中 ProjectContactsViewModel 设置为其 BindingContext。

我的 ContentView 看起来像这样:

public ProjectContactsView ()
    {
        //bind the view model to the context
        this.BindingContext = _viewModel;

        _list.ItemTemplate = new DataTemplate(typeof(ProjectContactsListCell));
        _list.IsGroupingEnabled = true;
        _list.GroupDisplayBinding = new Binding("Key");
        _list.GroupHeaderTemplate = new DataTemplate(typeof(ProjectContactsListHeaderCell));
        _list.HasUnevenRows = true;
    }

Solution

感谢@Sten Petrov 我设法解决了这个问题。我最终不得不在我的 ViewCell

中声明我的 ProjectContactsViewModel 的新实例

private TapGestureRecognizer tapGesturePhone = new TapGestureRecognizer ();
tapGesturePhone.BindingContext = new ProjectContactsViewModel ();

然后我以这种方式在 ViewCell 中绑定(bind)我的 TapGestureRecognizer:

tapGesturePhone.SetBinding<ProjectContactsViewModel> (TapGestureRecognizer.CommandProperty, vm => vm.DialPhoneCommand);
tapGesturePhone.SetBinding<ProjectContactsViewModel> (TapGestureRecognizer.CommandParameterProperty,vm => vm.PhoneNo);

从这里开始，我只需为 ViewModel 创建一个 Setter 和 Getter 并在构造函数中初始化命令:

 public Command DialPhoneCommand {get;set;}
 public string PhoneNo { get {return "http://google.com"; } set{ PhoneNo = value;}}
 public ProjectContactsViewModel ()
            {
                //Assign the dialcommand.
                DialPhoneCommand = new Command((phoneNo)=> 
                    Device.OpenUri(new Uri(phoneNo.ToString())));

            }

Answer 1

您可以在 ProjectContactsViewModel 中创建一个 Command 并将 tapGesture.Command 绑定(bind)到它。

绑定(bind)方式相同

 taskName.SetBinding(Label.TextProperty, "CompanyName");

您可以绑定(bind)点击手势的命令

    var tapGesturePhone = new TapGestureRecognizer ();
      tapGesturePhone.SetBinding(TapGestureRecognizer.CommandProperty,"DialPhoneCommand");
tapGesturePhone.SetBinding(TapGestureRecognizer.CommandParameterProperty,"PhoneNo");

      var phoneIcon = new Image {
        HorizontalOptions = LayoutOptions.Center,
        VerticalOptions = LayoutOptions.Center,
        Source = "phone.png" 
      };

  phoneIcon.GestureRecognizers.Add (tapGesturePhone);

命令可以在 ProjectContactsViewModel 中初始化(为简单起见):

... ProjectContactsViewModel { 
  public string PhoneNo {get;set;} 
  public Command DialPhoneCommand {get;set;}
  ...
  public ProjectContactsViewModel(){
    DialPhoneCommand = new Command((phoneNo)=> 
      Device.OpenUri(new Uri("tel:" + phoneNo ));
    );
  }
}