Wpf Observable集合和DataGrid不更新更改

nkkqxpd9  于 2023-10-22  发布在  其他
关注(0)|答案(2)|浏览(129)

我在视图模型中有一个可观察的集合，它实现了Bindable Base，如下所示。请看一下MoveUp和MoveDown方法，它们绑定到视图中的两个按钮。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的基于序列列中向上移动一步，并向下移动一步。这两种方法都非常有效。问题是只有当整个视图刷新时，更改才会显示在数据网格中。我的要求是，当按钮被单击时，我希望视图自动刷新。我为这么长的代码道歉。请帮帮忙！！.我有一些cs代码，以及为两个向上和向下按钮下指定的视图模型。代码中需要强调的指针只有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();
}
wpf

2条答案

按热度按时间
yh2wf1be

yh2wf1be1#

ObservableCollection将在更改时通知。没有理由手动执行此操作，因此您可以删除所有OnPropertyChanged("JobEntities");。这将为您提供更清洁的解决方案。
MSDN
WPF提供ObservableCollection类，该类是实现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。为此，最简单的方法是对Observable Collection中使用的元素实现INotifyPropertyChanged
我在示例中使用PRISM 5，因此它应该与您正在做的事情相当。你的代码有几个主要的设计更改。首先，我为我的Observable Collection使用了一个直接的属性。我们知道框架将处理对该集合的任何添加/删除操作。然后，为了在更改可观察集合中实体的属性时发出通知，我在TestEntity类本身中使用了一个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，注意BindableBase和我在更改时通知的事实。这允许DataGrid或您正在使用的任何东西被通知属性已更改。

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，实际上所有的TestEntity都需要实现INotifyPropertyChanged才能工作，但我使用PRISM BindableBase作为示例。

编辑

我在上面也发现了类似的问题。我认为你的略有不同，但他们在概念上重叠。看一下可能会有帮助。
Observable Collection Notify when property changed in MVVM

编辑

如果数据网格已排序，则前面的方法将不会更新网格。要处理这个问题，您需要刷新网格的视图，但是无法使用MVVM直接访问它。因此，要处理此问题，您需要使用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();
    }
}

TestEntity类没有改变，但这里又是这个类：

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，这里是我的XAML，显示了到新CollectionViewSource的绑定。

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

关于进一步的阅读，您可以参考MSDN文章。
这是另一个相关的问题/答案-Re-sort WPF DataGrid after bounded Data has changed

赞(0）分享  回复(0）举报  2023-10-22
ie3xauqp

ie3xauqp2#

我知道这是很古老的，但是，可能会帮助有人寻找答案。
在我的例子中，我已经将ObservableCollection设置为datagrid的项目源，并且从另一个线程中，我试图将另一个集合对象分配给源集合对象：

var _events = new ObservableCollection<Events>();
myDatagrid.ItemsSource = _events;

Task.Factory.StartNew(LoadEvents);

private void LoadEvents()
{
   var _tempData = GetDataFromEvtLogFile();
   Dispatcher.Invoke(()=> {
      _events = _tempData;
   });

}

仅分配似乎不会触发INotifyPropertyChange通知。所以我必须将每个条目添加到_events集合中，然后我的集合开始刷新。
变更：

foreach(var entry in _tempData)
{
    _events.Add(entry);
}
赞(0）分享  回复(0）举报  2023-10-22
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