如何防止列表视图中的所有按钮文本更改Xamarin形式

Question

I am wondering if someone could please help me or point me in the right direction. I have a Listview that binds to a Viewmodel , This listview has a label and a button . The listview is populated with music. When i press on the play button all the buttons that are populated with name of song in the listview has their name changed to stop , How do i prevent that from happening. Please find code below.

public class MusicViewModel : INotifyPropertyChanged
    {

        public MusicViewModel()
        {
            GetMusic();
            CommandText = "Play";
        }

        public List<AudioModel> _audioList;
        public List<AudioModel> AudioList
        {
            get { return _audioList; }
            set
            {
                _audioList = value;
                OnPropertyChanged();
            }
        }

        async void GetMusic()
        {
            var audioService = new AudioServices();
            AudioList = await audioService.GetAudioAsync();
        }
        private string _commandText;
        public string CommandText
        {
            get { return _commandText; }
            set
            {
                _commandText = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("CommandText"));
            }
        }
        public ICommand _playCommand;
        public ICommand PlayCommand
        {
            get
            {
                return _playCommand ?? (_playCommand = new Command((obj) =>
                {
                    var item = (obj as AudioModel);
                    var id = item.souID;
                    if (CommandText == "Play")
                    {
                        CrossMediaManager.Current.Play("http://Example.co.za/Example.asp?fldPRK=souID&PRKvalue=" + id + "&fldBLOB=sousound&TableName=Sounds_Sound_Details&ACT=BLOB&width=250&square=yes", MediaFileType.Audio);
                        CommandText = "Stop";
                    }
                    else if (CommandText == "Stop")
                    {
                        CrossMediaManager.Current.Stop();
                        CommandText = "Play";
                    }
                }));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }



<ListView ItemsSource="{Binding AudioList}" HasUnevenRows="True">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <ViewCell>
                        <Grid x:Name="Item">
                            <StackLayout>
                                <Label Text="{Binding souName}" />
                                <Button Text="{Binding Source={x:Reference Name=RINGTONE},Path=BindingContext.CommandText}" 
                                        Command="{Binding Source={x:Reference Name=RINGTONE},Path=BindingContext.PlayCommand}"  
                                        CommandParameter="{Binding Source={Reference Item},Path=BindingContext}"/>
                            </StackLayout>
                        </Grid>
                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
    </ListView>

Answer 1

You are binding each item to the same, shared command in the MusicViewModel . That is why all items are updated when you change it.

What you probably want is to add the command to the AudioModel . That way it will only update for that specific entry.