c# - 更新 ListView 项目值不工作 Windows Phone 8.1

Question

当我尝试更新 ListView 中插入元素的值时，我没有在手机上看到更改，但在调试消息中我看到了更改。这是我的代码。

 private void chat_LayoutUpdated(object sender, object e)
    {
        foreach (Message item in chat.Items)
        {
            item.MessageTime = GetRelativeDate(item.MessageDateTime);
            Debug.WriteLine(item.MessageTime); //Display changed value(Delta computed on step before) but on phone screen value didn't change;
        }

    }

GetRelativeDate//长函数，返回当前时间和消息发送时间之间的差值。

class Message // Model of chat message
{
    public string MessageText { get; set; }
    public string MessageTime { get; set; } // This value i want to change in ListView.
    public DateTime MessageDateTime { get; set; }
}

XAML

<TextBlock Grid.Column="0"
                FontSize="22"
                Text="{Binding MessageText}" />
                        <TextBlock
                Grid.Column="1"
                Grid.Row="1"
                FontSize="10"
                Text="{Binding MessageTime}" />

P/s 也许我需要一些更具体的东西来用作聊天窗口。

无论如何，谢谢你们，我将非常感谢任何答案或建议。

Answer 1

需要实现INofityPropertyChanged

MSDN: inotifypropertychanged Example

---

MSDN 文章中的示例:

public class DemoCustomer : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    // This method is called by the Set accessor of each property. 
    // The CallerMemberName attribute that is applied to the optional propertyName 
    // parameter causes the property name of the caller to be substituted as an argument. 
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    private DemoCustomer()
    {
    }

    private string customerNameValue = String.Empty;
    public string CustomerName
    {
        get
        {
            return this.customerNameValue;
        }

        set
        {
            if (value != this.customerNameValue)
            {
                this.customerNameValue = value;
                NotifyPropertyChanged();
            }
        }
    }
}