Question

我尝试将单例绑定到listview。单例是一个简单的日志记录类，它将所有新的传入日志记录消息放在一个可观察对象中。该对象绑定到我的xaml代码。

单身人士课程：

namespace Log
{
public sealed class CLog
{
    private CLog() { }

    private static object m_lock = new object();

    private static CLog _instance;
    public static CLog instance
    {
        get
        {
            if (_instance == null)
            {
                lock (m_lock)
                {
                    if (_instance == null)
                    {
                        _instance = new CLog();
                    }
                }
            }
            return _instance;
        }
    }

    private ObservableCollection<CLogMessage> _logs = new ObservableCollection<CLogMessage>();
    public ObservableCollection<CLogMessage> logs
    {
        get
        {
            if (_logs == null)
            {
                _logs = new ObservableCollection<CLogMessage>();
            }
            return _logs;
        }
    }

    public void AddString(string source, string message)
    {
        CLogMessage log = new CLogMessage();
        log.time = DateTime.Now;
        log.source = source;
        log.message = message;
        System.Windows.Application.Current.Dispatcher.Invoke(
            (Action)delegate()
        {
            logs.Add(log);
        });
    }
}

public sealed class CLogMessage
{
    public DateTime time { get; set; }
    public string source { get; set; }
    public string message { get; set; }
}

}

我在ListView中的绑定：

<Grid>
    <ListView ItemsSource="{Binding Source={x:Static local:CLog.instance}, Path=logs}">
        <ListView.View>
            <GridView>
                <GridViewColumn Header="Zeit" Width="140" DisplayMemberBinding="{Binding time}"/>
                <GridViewColumn Header="Quelle" Width="140" DisplayMemberBinding="{Binding source}"/>
                <GridViewColumn Header="Nachricht" Width="Auto" DisplayMemberBinding="{Binding message}"/>
            </GridView>
        </ListView.View>
    </ListView>
</Grid>

问题是我的视图没有更新。我通过来自不同类的简单CLog.instance.logs.Count（）随机测试了单例类的调试目的。绝对精细，我只是在我的视图中显示项目时遇到问题。我非常模糊的建议是我必须为绑定对象本身实现通知吗？

谢谢

Answer 1

我认为问题是由于listview从一开始就被绑定到null项源。由于我现在没有机器来测试，也许您可以通过更改_logs周围的代码来验证是否属实：

private ObservableCollection<CLogMessage> _logs = 
    new ObservableCollection<CLogMessage>();
public ObservableCollection<CLogMessage> logs
{
    get { return _logs; }
}

public void AddString(string source, string message)
{
    CLogMessage log = new CLogMessage();
    log.time = DateTime.Now;
    log.source = source;
    log.message = message;
    System.Windows.Application.Current.Dispatcher.Invoke(
        (Action)delegate()
    {
        _logs.Add(log);
    });
}

C＃WPF绑定到单例类中的可观察对象

1 个答案: