Do not binding to View in MVVM?

Question

On HomePage.xaml

 <Page.DataContext>
    <ViewModel:GetTweetVM/>
</Page.DataContext>

Listview

<!--Content-->
    <ListView x:Name="lstHome"
                             Grid.Row="2"
                             Margin="5"
                             ItemInvoked="lstHome_ItemInvoked"
                             ContainerContentChanging="lstHome_ContainerContentChanging" ItemsSource="{Binding statusList}">
        <ListView.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="auto"></ColumnDefinition>
                        <ColumnDefinition Width="*"></ColumnDefinition>
                        <ColumnDefinition Width="auto"></ColumnDefinition>
                    </Grid.ColumnDefinitions>

                    <Image x:Name="imgThumbnailUser" Source="{Binding}"></Image>

                    <StackPanel Orientation="Vertical" Grid.Column="1">
                        <StackPanel Orientation="Horizontal">
                            <TextBlock x:Name="txtName" Text="{Binding Text}"></TextBlock>
                            <TextBlock x:Name="txtUsername" Text="{Binding User.Name}" Foreground="#CCCCCC"></TextBlock>
                        </StackPanel>
                        <TextBlock x:Name="txtContentMessage" Text="{Binding User.Categories.Name}" TextTrimming="CharacterEllipsis" Foreground="#CCCCCC"></TextBlock>
                    </StackPanel>

                    <TextBlock x:Name="txtDateTime" Text="{Binding}" Foreground="#CCCCCC"></TextBlock>

                </Grid>
            </DataTemplate>
        </ListView.ItemTemplate>
    </control:ListView>

In GetTweetVM

 public class GetTweetVM
{
    TwitterContext twitter;

    public List<Status> statusList { get; set; }
    public GetTweetVM()
    {
        statusList = new List<Status>();
        if (SharedState.Authorizer != null)
        {
            twitter = new TwitterContext(SharedState.Authorizer);
            GetTweet();
        }
        else
            return;

    }

    public async void GetTweet()
    {
        //base.GetTweet();
        var objectStatus = await (from status in twitter.Status
                            where status.Type == LinqToTwitter.StatusType.Home && status.Count==10
                            select status).ToListAsync();
        foreach(var item in objectStatus)
        {
            statusList.Add(item);
        }
        string t = statusList[0].Text;
    }
}

The results :

string t will get value from statusList->"fadsvs.........."
On xaml that it do not binding to view.
Listview is no data.

I don't know where it is wrong? Please help me to fix it.

For starters, your `List` should really be an `ObservableCollection` or else modifications to the list will not update the `ListView`. — Decade Moon, Oct 23 '16 at 00:55
I don't understand your question. Given your lack of proficiency in English, you should take more time with the specifics. Make sure you include a good [mcve] that reliably reproduces the problem, and also make sure that you include _exact_ quotes of any error messages, exceptions, etc. that occur (preferably also in English...set the UI culture to "en" if you need to). Code and machine-generated output is universal and much easier to understand when there's otherwise a language barrier. — Peter Duniho, Oct 23 '16 at 02:25

score 1 · Answer 1 · edited May 23 '17 at 12:33

1

If I understand properly you have notification issue from ViewModel to View

Try below

public ObservableCollection<Status> statusList { get; set; }

ObservableCollection will ensure notification to UI when any item is added.

Do not binding to View in MVVM?

2 Answers2