UI (XAML) 没有更新属性但是在 ViewModel 中触发了 propertyChanged

Question

我在更新 windows phone 8 中的 XAML 时遇到了问题...属性在 XAML 中与 viewModel 绑定，触发了 propertyChange 并更改了属性的值。但是 XAML 中的属性成员只在开始时更新一次，从那以后它不会更新 XAML 中的任何东西......虽然属性在 ViewModel 中不断变化......这些属性属于观察集合的列表，最后属于观察集合绑定到 LongListSelector

我已将绑定模式更改为“双向”，但无用我已粘贴下面的代码。

期待帮助。

视图模型：

    private string _description;
    public string description
    {
        set
        {
            _description = value;
            RaisePropertyChanged("_description");
        }
        get
        {
            return _description;
        }
    }

    private double _progress_bar_Value;
    public double progress_bar_Value
    {
        set
        {
            _progress_bar_Value = value;
            RaisePropertyChanged("_progress_bar_Value");
        }
        get
        {
            return _progress_bar_Value; //= ProfileSetting.ProfileTab_DOB;

        }
    }



    private double _Total_Bytes;
    public double Total_Bytes
    {
        set
        {
            _Total_Bytes = value;
            RaisePropertyChanged("_Total_Bytes");
        }
        get
        {
            return _Total_Bytes;

        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void RaisePropertyChanged(string propertyName)
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

XAML：

`

                                    >
                <phone:LongListSelector.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Margin="0,0,0,0" Orientation="Vertical" 
                                    >
                            <TextBlock Text="{Binding description}"
                                       FontSize="18"
                                       TextWrapping="Wrap"
                                       Foreground="White" x:Name="Totalsize"
                                       />
                            <ProgressBar x:Name="Download_progressBar" 
                                         IsIndeterminate="False" 
                                         Maximum="100" 
                                         Height="10" 
                                         Width="400" 
                                         Value="{Binding progress_bar_Value}"
                                         Foreground="White"
                                         />
                            <TextBlock Text="{Binding Bytes_received}"
                                       FontSize="18"
                                       TextWrapping="Wrap"
                                       Foreground="White"
                                       x:Name="Total_received"
                               />
                        </StackPanel>
                    </DataTemplate>
                </phone:LongListSelector.ItemTemplate>
            </phone:LongListSelector>`

Answer 1

Raise Property Changed on public property not backing field（由 @HighCore 评论）