xamarin.android - 如何在 MvxListView 中绑定(bind) MvxListView 中的 ItemClick

Question

在下面的示例中，我想将 ItemClick 命令绑定(bind)到 MvxListView 中的项目。
在这里，我的 ViewModel 中有一个包含狗列表的人员列表。

ItemsSource HasDogs 绑定(bind)工作正常。

当 MvvmCross 试图将 ItemClick SelectDogCommand 绑定(bind)到 Viewmodel 中的 ICommand 时，我得到了这个异常。

[0:] 
MvxBind:Warning: 11,30 Unable to bind: source property source not found Property:SelectDogCommand on Person
[0:] MvxBind:Warning: 11,30 Unable to bind: source property source not found Property:SelectDogCommand on Person
12-04 15:05:03.062 I/mono-stdout(16338): MvxBind:Warning: 11,30 Unable to bind: source property source not found Property:SelectDogCommand on Person

希望您能提供帮助。

这是我的例子:

public class FirstViewModel:MvxViewModel
{
    private List<Person> _persons;
    public List<Person> Persons
    {
      get { return _persons; }
      set { _persons = value; }
    }

    private Cirrious.MvvmCross.ViewModels.MvxCommand<Dog> _selectDog;
    public System.Windows.Input.ICommand SelectDogCommand
    {
        get
        {
            _selectDog = _selectDog ?? new Cirrious.MvvmCross.ViewModels.MvxCommand<Dog>(SelectDog);
            return _selectDog;
        }
    }

    private void SelectDog(Dog item)
    {
        ShowViewModel<DetailViewModel>(new DetailViewModel.Parameters{dog = item});
    }

}

public class Person
{
    private string _name;
    private List<Dog> _hasDogs;

    public List<Dog> HasDogs
    {
      get { return _hasDogs; }
      set { _hasDogs = value; }
    }

    public string Name
    {
      get { return _name; }
      set { _name = value; }
    }
}

public class Dog{...}

Android View XML:

第一 View :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    ...>
    <TextView ...
        local:MvxBind="Text Persons"
    <Mvx.MvxListView
        ...
        local:MvxBind="ItemsSource Persons"
        local:MvxItemTemplate="@layout/item_person" />
</LinearLayout>

item_person:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    ...
    android:layout_height="200dp">
    <TextView
        ...
        local:MvxBind="Text Name" />
    <Mvx.MvxListView
        ...
        local:MvxBind="ItemsSource HasDogs; ItemClick SelectDogCommand"
        local:MvxItemTemplate="@layout/item_dog" />
</LinearLayout>

Answer 1

DataContext对于您的人员列表项是 Person - 所以你的SelectDogCommand需要成为 Person 的一部分类 - 例如就像是:

public class Person
{
    private string _name;
    private List<Dog> _hasDogs;

    public List<Dog> HasDogs
    {
      get { return _hasDogs; }
      set { _hasDogs = value; }
    }

    public string Name
    {
      get { return _name; }
      set { _name = value; }
    }

    private Cirrious.MvvmCross.ViewModels.MvxCommand<Dog> _selectDog;
    public System.Windows.Input.ICommand SelectDogCommand
    {
        get
        {
            _selectDog = _selectDog ?? new Cirrious.MvvmCross.ViewModels.MvxCommand<Dog>(dog => _parent.SelectDog(dog));
            return _selectDog;
        }
    }

    private FirstViewModel _parent;
    public Person(FirstViewModel parent)
    {
        _parent = parent;
    }
}

或者，您可以让 Person 从 MvxNavigatingObject(或 MvxPropertyChanged 或 MvxViewModel)继承 - 在这种情况下，ShowViewModel 方法也将在那里可用。