Wpf可观察集合和DataGrid未更新更改
Wpf可观察集合和DataGrid未更新更改
提问于 2014-11-14 09:31:32
我在视图模型中有一个observable集合，它实现了Bindable Base，如下所示。请看一下MoveUp和MoveDown方法，它们被绑定到视图中的两个按钮。每当按下向上按钮时，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，对于向下移动一步。这两种方法都能完美地工作。问题是，只有在刷新整个视图时，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！。我也有一些cs代码，以及在视图模型下面指定的向上和向下按钮。代码中需要强调的唯一指针是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();
}回答 1
Stack Overflow用户
回答已采纳
发布于 2014-11-14 13:27:57
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");。这将使您获得一个更干净的解决方案。
MSDN
WPF提供了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将只在集合本身发生更改(添加/删除)时发出通知。对列表中元素的任何修改都不会发送notify消息。为此，最简单的方法是实现Observable集合中使用的元素的INotifyPropertyChanged
我在示例中使用的是PRISM 5，因此它应该与您正在执行的操作相当。你的代码有几个主要的设计变化。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此集合的任何添加/删除操作。然后，为了在更改可观察集合中实体内的属性时发出通知，我在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收到属性更改的通知。
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，所有的TestEntity都需要实现INotifyPropertyChanged才能工作，但我使用的是PRISM BindableBase作为示例。
编辑
我在SO上发现了一个类似的问题。我认为你的略有不同，但它们在概念上是重叠的。回顾一下它可能会有所帮助。
Observable Collection Notify when property changed in MVVM
编辑
如果对数据网格进行了排序，则前面的方法将不会更新网格。要处理此问题，您需要刷新网格的视图，但无法使用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); }
}
}为了更清楚起见，下面是我的XAML，它显示了到新CollectionViewSource的绑定。
<DataGrid Grid.Row="1" ItemsSource="{Binding ViewSource.View}"></DataGrid>要进一步阅读，您可以参考关于这一点的MSDN文章。
这里有另一个相关的问题/答案- Re-sort WPF DataGrid after bounded Data has changed
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/26921537
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