【发布时间】：2019-01-14 10:54:35
【问题描述】：
我想通过单击 listview 的 viewcell 中的包和图像来更改标签文本和图像。我正在使用单击事件的命令，并在我的 ViewModelClass 中实现了它，它扩展了 InotifyPropertyChange。单击图像或标签时，我的视图未更新。请帮助。
公共类 BookPageViewModel : INotifyPropertyChanged, { #region 字段 private ObservableCollection feeds = new ObservableCollection();
public ObservableCollection<FeedsModel> Feeds {
get
{
return feeds;
}
set {
if(value != feeds)
{
feeds = value;
OnPropertyChanged("Feeds");
}
}
}
private ICommand onLikePostClicked;
public ICommand OnLikePostClicked
{
get { return onLikePostClicked; }
}
public DayBookPageViewModel(Page page, SfListView sfListView)
{
GetAllFeeds(Settings.UserIdSettings);
this.page = page;
this.sfListView = sfListView;
#region Commands execution
onLikePostClicked = new Command((e) =>
{
var item = (e as FeedsModel);
if (!string.IsNullOrEmpty(item.Love))
{
bool like_status = false;
string[] strarray = item.Love.Split(',');
for (int i = 0; i < strarray.Length; i++)
{
if (strarray[i] == Settings.UserIdSettings)
{
like_status = true;
break;
}
else
{
like_status = false;
}
}
if(like_status)
{
// unlike
if (!NetworkConnectionClass.GetInstance().IsConnectedToInternet())
ShowAlerts.GetInstance().ACRLibAlert(Strings.InternetAlert, Strings.Ok);
else
{
if (item != null)
{
Device.BeginInvokeOnMainThread(delegate
{
item.LikeImageSource = ImageSource.FromFile("like_hover");
item.LikeLabelColor = (Color)Application.Current.Resources["defaultLabels_color"];
OnPropertyChanged("Feeds");
});
DislikeApi dislikePostApi = new DislikeApi(this, this);
dislikePostApi.DisLikePost(Settings.UserIdSettings, item.postId.ToString());
}
}
}
else
{
// like
if (!NetworkConnectionClass.GetInstance().IsConnectedToInternet())
ShowAlerts.GetInstance().ACRLibAlert(Strings.InternetAlert, Strings.Ok);
else
{
if (item != null)
{
//Todo;
//********* UI not updating : need to fixed ***********
Device.BeginInvokeOnMainThread(delegate
{
item.LikeImageSource = ImageSource.FromFile("like");
item.LikeLabelColor = (Color)Application.Current.Resources["appThemeColor"];
OnPropertyChanged("Feeds");
});
LikePostApi likePostApi = new LikePostApi(this, this);
likePostApi.LikePost(Settings.UserIdSettings, item.postId.ToString());
}
}
}
}
else
{
if (!NetworkConnectionClass.GetInstance().IsConnectedToInternet())
ShowAlerts.GetInstance().ACRLibAlert(Strings.InternetAlert, Strings.Ok);
else
{
if (item != null)
{
//Todo;
//********* UI not updating : need to fixed ***********
Device.BeginInvokeOnMainThread( delegate
{ if (!item.Love.Contains(Settings.UserIdSettings))
{
likeimageSource = ImageSource.FromFile("like");
item.LikeImageSource = ImageSource.FromFile("like");
item.LikeLabelColor = (Color)Application.Current.Resources["appThemeColor"];
OnPropertyChanged("Feeds");
});
#endregion
}
}
// This is inside the viewcell of a listview
<Label x:Name="likeLabel" TextColor="{Binding LikeLabelColor, Mode=TwoWay}" Text="Like " LineBreakMode="CharacterWrap" FontSize="12" Grid.Row="0" Grid.Column="1">
<Label.Margin>
<OnPlatform x:TypeArguments="Thickness">
<On Platform="iOS" Value="0,15.5,0,0" />
<On Platform="Android" Value="0,14,0,0" />
</OnPlatform>
</Label.Margin>
<Label.GestureRecognizers>
<TapGestureRecognizer Command="{Binding Path=BindingContext.OnLikePostClicked, Source={x:Reference customListView}}" CommandParameter ="{Binding .}" NumberOfTapsRequired="1" />
</Label.GestureRecognizers>
</Label>
【问题讨论】：
标签： listview mvvm xamarin.forms