將ItemSource分配給ListView之后更新ListView

Question

我對這個話題很困惑，我只是在用一個Single ListView。

            <ListView.ItemTemplate >
            <DataTemplate >
                <Grid>

                    <Grid.RowDefinitions>
                        <RowDefinition Height="*"/>
                        <RowDefinition Height="*"/>
                        <RowDefinition Height="*"/>
                    </Grid.RowDefinitions>

                    <Image Source="Assets/button_register.png"  Stretch="None" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="8,15,8,8" />
                        <TextBlock Text="{Binding Sender}" FontSize="18" Foreground="Black" FontWeight="Bold" HorizontalAlignment="Center" Margin="0,12,0,0"/>

                    <Image Source="Assets/button_register.png"  Grid.Row="1" Stretch="None" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="4,0" />
                    <TextBlock Text="{Binding Receiver}"  FontSize="18" Foreground="Black" FontWeight="Bold" HorizontalAlignment="Center" Grid.Row="1" Margin="0,12,0,0" VerticalAlignment="Top"/>
                    <Image Source="Assets/scroll_line_addcategory.png" Grid.Row="2" Stretch="None" HorizontalAlignment="Right" VerticalAlignment="Bottom" Margin="4,8,4,0" />
                </Grid>


            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

並且此列表視圖與以下類綁定

 public class User : INotifyPropertyChanged
{
    public string Sender = string.Empty;
    public string Receiver = string.Empty;
    public string SenderVisibility = string.Empty;
    public string ReceiverVisibility = string.Empty;
    public event PropertyChangedEventHandler PropertyChanged;

    public string send
    {
        get
        {
            return this.Sender;
        }
        set
        {
            if (value != this.Sender)
            {
                this.Sender = value;
                NotifyPropertyChanged("send");
            }
        }
    }
    public string receive
    {
        get
        {
            return this.Receiver;
        }
        set
        {
            if (value != this.Receiver)
            {
                this.Receiver = value;
                NotifyPropertyChanged("receive");
            }
        }
    }
    public string receivevisible
    {
        get
        {
            return this.ReceiverVisibility;
        }
        set
        {
            if (value != this.ReceiverVisibility)
            {
                this.ReceiverVisibility = value;
                NotifyPropertyChanged("receivevisible");
            }
        }
    }
    public string sendervisibility
    {
        get
        {
            return this.SenderVisibility;
        }
        set
        {
            if (value != this.SenderVisibility)
            {
                this.SenderVisibility = value;
                NotifyPropertyChanged("sendervisibility");
            }
        }
    }
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

在那時加載應用程序時，我只是在6時加載了靜態數據。

  private void Page_Loaded(object sender, RoutedEventArgs e)
    {
        //List<User> ls = new List<User>();
        for (int a = 0; a <= 5; a++)
        {
            User u = new User();
            u.Sender = "Hello";
            u.Receiver = "World";
            ls.Add(u);
        }
        lst1.ItemsSource = ls;
        Debug.WriteLine("Ls Count :: " + ls.Count);


    }

但是問題再次出現，我在同一源列表中添加數據。分配源后，但源列表不是更新。

   private void btnSend_Click(object sender, RoutedEventArgs e)
    {
     User n=new User(){
         Sender="Chirag",
         Receiver="Solanki"
     };
     ls.Add(n);
     lst1.ItemsSource = ls;
    }

因此，Plz如果有人有任何出色的想法，請幫助我。

Answer 1

只需設置ItemsSource就足夠了。 再次設置不會改變任何內容。 代替List<User>您應該使用ObservableCollection<User> 。 它將自動處理列表中的更改。

此外，您在User類中有很多錯誤。 這是固定代碼：

class User : INotifyPropertyChanged
{
    private string sender = string.Empty;
    private string receiver = string.Empty;
    private string senderVisibility = string.Empty;
    private string receiverVisibility = string.Empty;

    public string Sender
    {
        get
        {
            return sender;
        }
        set
        {
            if (value != this.sender)
            {
                this.sender = value;
                NotifyPropertyChanged("Sender");
            }
        }
    }

    public string Receiver
    {
        get
        {
            return this.receiver;
        }
        set
        {
            if (value != this.receiver)
            {
                this.receiver = value;
                NotifyPropertyChanged("Receiver");
            }
        }
    }
    public string ReceiverVisibility
    {
        get
        {
            return this.receiverVisibility;
        }
        set
        {
            if (value != this.receiverVisibility)
            {
                this.receiverVisibility = value;
                NotifyPropertyChanged("ReceiverVisibility");
            }
        }
    }
    public string SenderVisibility
    {
        get
        {
            return this.senderVisibility;
        }
        set
        {
            if (value != this.senderVisibility)
            {
                this.senderVisibility = value;
                NotifyPropertyChanged("SenderVisibility");
            }
        }
    }

    private void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

調用NotifyPropertyChanged(propertyName) ， propertyName的值必須與propertyName的名稱匹配。 您搞砸了屬性和字段。 這些私有的小寫字母被歸檔。 駱駝公案的值是屬性。 在XAML中，您必須綁定屬性而不是字段。