Wpf Observable集合和DataGrid不更新更改

Question

我有一个实现可绑定基本如下,请看看他们均绑定了两个按钮,在视图中上移和下移方法视图模型的观察的集合.当按下向上按钮时,我希望数据网格中的选定行在数据库中基于序列列向上移动一步并向下移动一步.两种方法都可以完美地工作.问题是只有在刷新整个视图时才会在数据网格中显示更改.我的要求是单击按钮时我希望视图自动刷新.我为这么长的代码道歉.请帮忙!!!!.我在viewmodel下面指定的向上和向下按钮都有一些cs代码.只需要强调的代码中的指针是ObservableCollection JobEntities,MoveUp和MoveDown命令.

ViewModel.cs:

public class JobConfigurationViewModel : BindableBase
{


    public JobConfigurationLogic JobConfigurationLogic =
        new JobConfigurationLogic(new JobConfigurationResultsRepository());

    public SrcDestConfigurationLogic SrcDestConfigurationLogic =
        new SrcDestConfigurationLogic(new SrcDestCofigurationRepository());

    private string _enterprise;

    public string Enterprise
    {
        get { return _enterprise; }
        set { SetProperty(ref _enterprise, value); }
    }

    private int currentJobID;
    private int currentSequence;
    private int previousJobID;
    private int previousSequence;
    private string _site;

    public string Site
    {
        get { return _site; }
        set { SetProperty(ref _site, value); }
    }

    private int _siteID;

    public int SiteID
    {
        get { return _siteID; }
        set { SetProperty(ref _siteID, value); }
    }

    private ObservableCollection<JobConfigurationResults> _jobEntities;

    public ObservableCollection<JobConfigurationResults> JobEntities
    {
        get { return _jobEntities; }
        set
        {
            SetProperty(ref _jobEntities, value); 
            this.OnPropertyChanged("JobEntities");
        }
    }

    //Source System List for Job
    private List<SourceSiteSystem> _lstJobSrcSystems;

    public List<SourceSiteSystem> LstJobSrcSystems
    {
        get { return _lstJobSrcSystems; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            SetProperty(ref _lstJobSrcSystems, value);
        }
    }

    //Deestination  System List for Job
    private List<DestinationSiteSystem> _lstJobDestSystems;

    public List<DestinationSiteSystem> LstJobDestSystems
    {
        get { return _lstJobDestSystems; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            SetProperty(ref _lstJobDestSystems, value);
        }
    }

    //the Selected Source Site system ID 
    private int _selectedSrcSiteSystemId = 0;

    public int SelectedSrcSiteSystemId
    {
        get { return _selectedSrcSiteSystemId; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            SetProperty(ref _selectedSrcSiteSystemId, value);
        }
    }

    //the Selected Source Site system from the dropdown
    private SourceSiteSystem _selectedSrcSiteSystem;

    public SourceSiteSystem SelectedSrcSiteSystem
    {
        get { return _selectedSrcSiteSystem; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            if (value != null)
            {
                SetProperty(ref _selectedSrcSiteSystem, value);
                SelectedSrcSiteSystemId = SelectedSrcSiteSystem.SiteSystemId;
            }
        }
    }

    //the Selected Destination Site system ID 
    private int _selectedDestSiteSystemId = 0;

    public int SelectedDestSiteSystemId
    {
        get { return _selectedDestSiteSystemId; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            SetProperty(ref _selectedDestSiteSystemId, value);
        }
    }

    //the Selected Destination Site system from the dropdown
    private DestinationSiteSystem _selectedDestSiteSystem;

    public DestinationSiteSystem SelectedDestSiteSystem
    {
        get { return _selectedDestSiteSystem; }
        set
        {
            //Using bindable base setproperty method instead of older inotify prop changed method
            if (value != null)
            {
                SetProperty(ref _selectedDestSiteSystem, value);
                SelectedDestSiteSystemId = SelectedDestSiteSystem.SiteSystemId;
            }
        }
    }

    private JobConfigurationResults _jeJobConfigurationResults;

    public JobConfigurationResults JEJobConfigurationResults
    {
        get { return _jeJobConfigurationResults; }
        set { _jeJobConfigurationResults = value; }
    }

    private List<JobTaskConfiguration> _taskSelectionList = new List<JobTaskConfiguration>();

    private CancellationTokenSource _source;

    private RelayCommand<object> _commandSaveInstance;
    private RelayCommand<object> _hyperlinkInstance;
    private RelayCommand<object> _commandRunJob;
    private RelayCommand<object> _upCommand;
    private RelayCommand<object> _downCommand;
    private IEventAggregator _aggregator;


    /// <summary>
    /// This is a Subscriber to the Event published by EnterpriseViewModel
    /// </summary>
    /// <param name="agg"></param>
    public JobConfigurationViewModel(IEventAggregator agg)
    {
        _aggregator = agg;
        PubSubEvent<Message> evt = _aggregator.GetEvent<PubSubEvent<Message>>();
        evt.Subscribe(message => Enterprise = message.Enterprise.ToString(), ThreadOption.BackgroundThread);
        evt.Subscribe(message => Site = message.Site.ToString(), ThreadOption.BackgroundThread);
        evt.Subscribe(message => SiteID = message.SiteID, ThreadOption.BackgroundThread);
        //evt.Unsubscribe();
        StartPopulate();
    }

    private async void StartPopulate()
    {
        await TaskPopulate();
    }

    //This is to ensure that the publisher has published the data that is needed for display in this workspace
    private bool TaskProc()
    {
        Thread.Sleep(500);
        PubSubEvent<Message> evt = _aggregator.GetEvent<PubSubEvent<Message>>();
        evt.Subscribe(message => Enterprise = message.Enterprise.ToString(), ThreadOption.BackgroundThread);
        evt.Subscribe(message => Site = message.Site.ToString(), ThreadOption.BackgroundThread);
        evt.Subscribe(message => SiteID = message.SiteID, ThreadOption.BackgroundThread);
        return DoPopulate();
    }

    private Task<bool> TaskPopulate()
    {
        _source = new CancellationTokenSource();
        return Task.Factory.StartNew<bool>(TaskProc, _source.Token);
    }

    /// <summary>
    /// This method handles the populating of the Source and Destination Dropdowns and the Job entity and Task Datagrid
    ///   This is mainly driven by the Site selected in the previous workspace
    /// </summary>
    /// <returns></returns>

    private bool DoPopulate()
    {
        PopulateSourceDestinations(this.SiteID);

        return true;
    }

    /// <summary>
    /// this method displays all entities and tasks for the site.
    /// This is done async so that the Publisher thread is not held up
    /// </summary>
    public void GetJobConfigurationResults()
    {
        if (SelectedSrcSiteSystem == null)
        {
            SelectedSrcSiteSystem = LstJobSrcSystems[0];
        }
        if (SelectedDestSiteSystem == null)
        {
            SelectedDestSiteSystem = LstJobDestSystems[0];
        }
        SelectedSrcSiteSystemId = SelectedSrcSiteSystem.SiteSystemId;
        SelectedDestSiteSystemId = SelectedDestSiteSystem.SiteSystemId;
        var jobConfigurationResults = new JobConfigurationResults
        {
            SourceId = SelectedSrcSiteSystemId,
            DestinationId = SelectedDestSiteSystemId
        };
        JobEntities = new ObservableCollection<JobConfigurationResults>();
        JobEntities = JobConfigurationLogic.GetResults(jobConfigurationResults.SourceId,
            jobConfigurationResults.DestinationId);
        _taskSelectionList = new List<JobTaskConfiguration>(JobEntities.Count * 3);
    }

    /// <summary>
    /// //Adding a method to pupulate the Source and Destination dropdown lists. 
    /// This is done async so that the Publisher thread is not held up
    /// </summary>
    /// 
    /// 
    public async void PopulateSourceDestinations(int siteId)
    {
        this.LstJobSrcSystems = SrcDestConfigurationLogic.LoadSourceSiteSystems(siteId);
        this.LstJobDestSystems = SrcDestConfigurationLogic.LoadDestinationSystems(siteId);
        GetJobConfigurationResults();
    }

    public ICommand HyperlinkCommand
    {
        get
        {
            if (_hyperlinkInstance == null)
                _hyperlinkInstance = new RelayCommand<object>(openDialog);
            return _hyperlinkInstance;
        }
    }

    private void openDialog(object obj)
    {
        JobConfigurationResults results = obj as JobConfigurationResults;
        JEJobConfigurationResults = JobEntities.SingleOrDefault(x => x.JobEntityId == results.JobEntityId);

    }

    public ICommand CommandSave
    {
        get
        {
            if (_commandSaveInstance == null)
                _commandSaveInstance = new RelayCommand<object>(saveJobConfigurationChanges);
            return _commandSaveInstance;
        }
    }

    public ICommand CommandRunJob
    {
        get { return _commandRunJob ?? (_commandRunJob = new RelayCommand<object>(RunJob)); }
    }

    /// <summary>
    /// this saves all the changes in the selection made by the user 
    /// </summary>
    /// <param name="ob"></param>
    public void saveJobConfigurationChanges(object ob)
    {
        foreach (var job in JobEntities)
        {
            int jobEntityId = job.JobEntityId;
            foreach (var task in job.TaskDetails)
            {
                int id = task.JobTask_ID;
                bool isSelected = task.IsSelected;
                _taskSelectionList.Add(task);
            }
        }
        JobConfigurationLogic.UpdateTaskSelection(_taskSelectionList);
    }


    public ICommand UpCommand
    {
        get
        {
            if (_upCommand == null)
                _upCommand = new RelayCommand<object>(MoveUp);
            return _upCommand;
        }
    }

    private void MoveUp(object obj)
    {

        if (obj != null)
        {
            JobConfigurationResults results = obj as JobConfigurationResults;
            currentJobID = results.JobEntityId;
            currentSequence = results.SequenceOrder - 1;
            try
            {
                JobConfigurationResults res = _jobEntities.SingleOrDefault(n => n.SequenceOrder == currentSequence);
                previousJobID = res.JobEntityId;
                previousSequence = res.SequenceOrder + 1;
                // JobConfigurationLogic.UpdateSequence(currentJobID, previousSequence, previousJobID, currentSequence);
                JobConfigurationLogic.UpdateSequence(currentSequence, currentJobID, previousSequence, previousJobID);
                OnPropertyChanged("JobEntities");
            }
            catch (NullReferenceException)
            {
                MessageBox.Show("Can't move the top record");
            }

        }
        else
        {
            MessageBox.Show("Please Select a row that you want to sort");
        }
    }

    public ICommand DownCommand
    {
        get
        {
            if (_downCommand == null)
                _downCommand = new RelayCommand<object>(MoveDown);
            return _downCommand;
        }
    }

    private void MoveDown(object obj)
    {
        if (obj != null)
        {
            JobConfigurationResults results = obj as JobConfigurationResults;
            currentJobID = results.JobEntityId;
            currentSequence = results.SequenceOrder + 1;
            try
            {
                JobConfigurationResults res = _jobEntities.SingleOrDefault(a => a.SequenceOrder == currentSequence);
                previousJobID = res.JobEntityId;
                previousSequence = res.SequenceOrder - 1;
                JobConfigurationLogic.UpdateSequence(currentSequence, currentJobID, previousSequence, previousJobID);
                OnPropertyChanged("JobEntities");
            }
            catch (NullReferenceException)
            {

                MessageBox.Show("You have reached the end");
            }

        }
        else
        {
            MessageBox.Show("Please Select a row that you want to sort");
        }
    }

    /// <summary>
    /// Execute an etl job using the current job id
    /// </summary>
    private void RunJob(object obj)
    {
        JobEngine jobEngine = new JobEngine();
        var jobId = JobEntities[0].JobId;
        jobEngine.ProcessJob(jobId);
    }
} 

CS代码:

private void btnup_Click(object sender, RoutedEventArgs e)
{

    dgEntities.Items.Refresh();
    //dgEntities.GetBindingExpression(DataGrid.ItemsSourceProperty).UpdateTarget();
}

private void btndown_Click(object sender, RoutedEventArgs e)
{
    dgEntities.GetBindingExpression(DataGrid.ItemsSourceProperty).UpdateTarget();
}

Answer 1

一个ObservableCollection会通知上的变化.没有理由手动执行,因此您可以删除所有OnPropertyChanged("JobEntities");.这将使您获得更清洁的解决方案.

MSDN

WPF提供了ObservableCollection类,它是实现INotifyCollectionChanged接口的数据集合的内置实现.

下一部分是ObservableCollection只会通知集合本身的更改(添加/删除).对列表中元素的任何修改都不会发送通知消息.要做到这一点,最简单的方法是实现INotifyPropertyChangedObservable Collection中使用的元素

我在示例中使用PRISM 5,因此它应该与您正在做的事情完全相同.你的代码有几个主要的设计变化.首先,我正在为我的Observable Collection使用直接属性.我们知道框架将处理对此集合的任何添加/删除操作.然后,当我在可观察集合中更改实体内的属性时,我已经在TestEntity类本身中使用了notify属性.

public class MainWindowViewModel : BindableBase
{
    //Notice no OnPropertyChange, just a property
    public ObservableCollection<TestEntity> TestEntities { get; set; }

    public MainWindowViewModel()
        : base()
    {
        this.TestEntities = new ObservableCollection<TestEntity> {
            new TestEntity { Name = "Test", Count=0},
            new TestEntity { Name = "Test1", Count=1},
            new TestEntity { Name = "Test2", Count=2},
            new TestEntity { Name = "Test3", Count=3}
        };

        this.UpCommand = new DelegateCommand(this.MoveUp);
    }

    public ICommand UpCommand { get; private set; }

    private void MoveUp()
    {
        //Here is a dummy edit to show the modification of a element within the observable collection
        var i = this.TestEntities.FirstOrDefault();
        i.Count = 5;

    }
}

这是我的实体,请注意BindableBase我在变更时通知的事实.这样可以DataGrid通知您正在使用的任何内容,即该属性已更改.

public class TestEntity : BindableBase {
    private String _name;
    public String Name
    {
        get { return _name; }
        set { SetProperty(ref _name, value); }
    }
    //Notice I've implemented the OnPropertyNotify (Prism uses SetProperty, but it's the same thing)
    private Int32 _count;
    public Int32 Count
    {
        get { return _count; }
        set { SetProperty(ref _count, value); }
    }
}

现在真的TestEntity需要实现INotifyPropertyChanged这个工作,但我使用PRISM BindableBase作为例子.

编辑

我在SO上发现了类似的问题.我认为你的略有不同,但它们在概念上重叠.它可能有助于审视它.

可观察集合在MVVM中更改属性时通知

编辑

如果数据网格已排序,则以前的方法不会更新网格.要处理此问题,您需要刷新网格视图,但无法使用MVVM直接访问它.所以要处理这个你想要使用一个CollectionViewSource.

public class MainWindowViewModel : BindableBase
{
    //This will bind to the DataGrid instead of the TestEntities
    public CollectionViewSource ViewSource { get; set; }
    //Notice no OnPropertyChange, just a property
    public ObservableCollection<TestEntity> TestEntities { get; set; }

    public MainWindowViewModel()
        : base()
    {
        this.TestEntities = new ObservableCollection<TestEntity> {
        new TestEntity { Name = "Test", Count=0},
        new TestEntity { Name = "Test1", Count=1},
        new TestEntity { Name = "Test2", Count=2},
        new TestEntity { Name = "Test3", Count=3}
    };

        this.UpCommand = new DelegateCommand(this.MoveUp);

        //Initialize the view source and set the source to your observable collection
        this.ViewSource = new CollectionViewSource();
        ViewSource.Source = this.TestEntities;
    }

    public ICommand UpCommand { get; private set; }

    private void MoveUp()
    {
        //Here is a dummy edit to show the modification of a element within the observable collection
        var i = this.TestEntities.FirstOrDefault();
        i.Count = 5;
        //Now anytime you want the datagrid to refresh you can call this.
        ViewSource.View.Refresh();
    }
}

该TestEntity级不会改变,但这里又是类:

public class TestEntity : BindableBase
{
    private String _name;
    public String Name
    {
        get { return _name; }
        set { SetProperty(ref _name, value); }
    }
    //Notice I've implemented the OnPropertyNotify (Prism uses SetProperty, but it's the same thing)
    private Int32 _count;
    public Int32 Count
    {
        get { return _count; }
        set { SetProperty(ref _count, value); }
    }
}

为了澄清,这是我的XAML显示绑定到新的CollectionViewSource.

<DataGrid  Grid.Row="1" ItemsSource="{Binding ViewSource.View}"></DataGrid>

有关进一步阅读,请参阅MSDN上的文章.

这是另一个相关的问题/答案 - 在有界数据发生变化后重新排序WPF DataGrid