I Follow MVVM model for my application, I have a textbox which acts as an input to filter the collection. I understood observablecollection filter using lambda expression but i couldn't understand collectionviewsource methods. how can i implement collectionviewsource methods using this.
Here is my viewmodel class:
private ObservableCollection<SPFetchCREntity> _CRmappings2 = new ObservableCollection<SPFetchCREntity>();
public ObservableCollection<SPFetchCREntity> CRmappings2
{
get { return _CRmappings2; }
set
{
_CRmappings2 = value;
RaisePropertyChanged("CRmappings2");
}
}
public ICollectionView AllCRSP
{ get; private set;}
public void UpdatePopList()
{
CRmappings2 = new ObservableCollection<SPFetchCREntity>(crentities.Where(p => p.MU_Identifier == selectmu.ToString()).ToList());
}
Bind to the ICollectionView and filter this one:
public void UpdatePopList()
{
CRmappings2 = new ObservableCollection<SPFetchCREntity>(crentities.ToList());
AllCRSP = CollectionViewSource.GetDefaultView(CRmappings2);
AllCRSP.Filter = obj =>
{
SPFetchCREntity entity = obj as SPFetchCREntity;
return entity != null && entity.MU_Identifier == selectmu.ToString();
};
}
private string _selectmu;
public string Selectmu
{
get { return _selectmu; }
set { _selectmu = value; AllCRSP.Refresh(); } //<-- refresh the ICollectionView whenever the selectmu property gets set or when you want to refresh the filter
}
Related
On my viewModel I developed this code that will allow me to implement a research filter:
public ICollection<Nc> Ncs
{
get
{
var ncs = _ncManager.Ncs;
_ncCollectionView = CollectionViewSource.GetDefaultView(ncs);
_ncCollectionView.Filter = _DoesNcMatchFileNameFilter;
return ncs;
}
}
private ICollectionView _ncCollectionView;
This method works, but if I try to implement another similar method in another viewModel:
private ObservableCollection<Material> _materials;
public ObservableCollection<Material> materials
{
get
{
var materials = Material.Name;
_materialCollectionView = (CollectionViewSource)CollectionViewSource.GetDefaultView(materials);
_materialCollectionView.Filter = _DoesMaterialMatchFileNameFilter;
return Materials;
}
}
private CollectionViewSource _materialCollectionView;
I get an error: CollectionViewSrouce.Filter can only appear on the left hand side of += or -=".
Why can't I do the same thing? What did I do wrong?
I've tried to read this page ObservableCollection<> vs. List<> but it didn't help me.
should _materialCollectionView not be of type ICollectionView?
So:
private ObservableCollection<Material> _materials;
public ObservableCollection<Material> materials
{
get
{
var materials = Material.Name;
_materialCollectionView = CollectionViewSource.GetDefaultView(materials);
_materialCollectionView.Filter = _DoesMaterialMatchFileNameFilter;
return Materials;
}
}
private ICollectionView _materialCollectionView;
Is it possible to convert IEnumerable to a Custom Class that is inherting from ObservableCollection class?
Reason is I want to select only a filtered set of items on the get. I want to implement it on the get because lots of other properties reference CustomItems and perform processes on the items, but I want to somehow make it process filtered set of items depending if a value is enabled or not.
Below is code to help explain what I want to achieve:
public class CustomItemsCollection : ObservableCollection<ItemViewModel>
{
public ListView ListView { get; set; }
public void ScrollToItem(object item = null)
{
//Some custom Code
}
}
And here is my property that I want to customize:
private CustomItemsCollection _CustomItems = null;
[JsonProperty]
public CustomItemsCollection CustomItems
{
get
{
if (_CustomItems != null)
{
if(SomeValueIsEnabled)
{
var filteredItems = _CustomItems.Where(c => c.Property.equals(SomeValue));
var castedItems = (CustomItemsCollection)filteredItems;
return castedItems;
}
return _CustomItems;
}
_CustomItems = new CustomItemsCollection();
_CustomItemsChangedSource = new CollectionChangedWeakEventSource();
_CustomItemsChangedSource.SetEventSource(_CustomItems);
_CustomItemsChangedSource.CollectionChanged += _CustomItemsChangedSource_CollectionChanged;
return _CustomItems;
}
set { _CustomItems = value; RaisePropertyChanged("CustomItems"); }
}
Specifically, this part:
if(SomeValueIsEnabled)
{
var filteredItems = _CustomItems.Where(c => c.Property.equals(SomeValue));
var castedItems = (CustomItemsCollection)filteredItems;
return castedItems;
}
Is this possible / or maybe wrong? What is the best practice to do it?
Thank you!
You can't just cast it, but you can create an instance of CustomItemsCollection and initialize it with filteredItems.
Add a constructor to your custom class that passes through to the appropriate ObservableCollection constructor:
public class CustomItemsCollection : ObservableCollection<ItemViewModel>
{
public CustomItemsCollection(IEnumerable<ItemViewModel> items)
: base(items) { }
// your other code here
}
Then you can do this:
var filteredItems = _CustomItems.Where(c => c.Property.equals(SomeValue));
var collection = new CustomItemsCollection(filteredItems);
return collection;
Try with this code:
var filteredItems = _CustomItems.Where(c => c.Property.equals(SomeValue))
.Select(pre=> new ItemViewModel(){
//add info here
});
var castedItems = new CustomItemsCollection(filteredItems);
I'm filtering a listcollectionview in viewModel 1 based on selectionchanged of datagrid in viewModel 2. To do this I use mvvm messaging. Each time the selection of the datagrid changes a message is send to update my listcollectionview. This all works well.
Now I need to use the string value of this message to pass into the filter. The problem is that I can only use the string value in the updateShotList method but not into the bool IsMatch. How can I make this work, or how can I use the string value of the message as a variable in my viewmodel.
This is how my viewmodel looks like.
private ObservableCollection<Shot> _allShots = new ObservableCollection<Shot>();
public ObservableCollection<Shot> AllShots
{
get { return _allShots; }
set { _allShots = value; RaisePropertyChanged();}
}
private ListCollectionView _allShotsCollection;
public ListCollectionView AllShotsCollection
{
get
{
if (_allShotsCollection == null)
{
_allShotsCollection = new ListCollectionView(this.AllShots);
}
return _allShotsCollection;
}
set
{
_allShotsCollection = value; RaisePropertyChanged();
}
}
private void UpdateShotList(string SceneNr) // value sceneNr comes from message from viewmodel 2
{
_allShotsCollection.IsLiveFiltering = true;
_allShotsCollection.Filter = new Predicate<object>(IsMatchFound);
}
bool IsMatchFound(object obj)
{
=====> if (obj as Shot != null && (obj as Shot).SceneNumber == "?????") // Here I need the value of string ScenNr that comes from the message.
{
return true;
}
return false;
}
public ShotListViewModel()
{
Messenger.Default.Register<string>(this, "UpdateShotList", UpdateShotList);
}
You can create your predicate as a lambda expression and close over SceneNr to capture it:
_allShotsCollection.Filter = o =>
{
var shot = o as Shot;
return shot != null && shot.SceneNumber == SceneNr;
};
Alternatively, simply introduce an instance variable to contain your filter string and update it each time you receive a message:
private string _sceneNr;
private void UpdateShotList(string sceneNr)
{
// ...
_sceneNr = sceneNr;
}
bool IsMatchFound(object obj)
{
var shot = obj as Shot;
return shot != null && shot.SceneNumber == _sceneNr;
}
I am trying to use the following code example from the Infragistics site and I'd like edits in the XamDataCards to be reflected in the XamDataGrid. However, my DataSource for the XamDataGrid is an ObservableCollection<Companies> in my ViewModel. How can I also bind to the card and relay updates back to my Companies object in the ViewModel?
<igDP:XamDataGrid x:Name="dgCompanies" Theme="IGTheme" DataSource="{Binding Companies}" SelectedDataItemsScope="RecordsOnly">
<igDP:XamDataGrid.FieldSettings>
<igDP:FieldSettings CellClickAction="SelectCell" AllowEdit="True"/>
</igDP:XamDataGrid.FieldSettings>
</igDP:XamDataGrid>
<igDP:XamDataCards x:Name="XamDataCards1"
Grid.Row="1"
DataSource="{Binding Path=SelectedDataItems, ElementName=dgCompanies}"
Theme="IGTheme">
Edit: Added ViewModel
public class CompanyMgmtViewModel : ViewModelBase
{
private ObservableCollection<Object> _Companies = null;
public ObservableCollection<Object> Companies
{
get { return _Companies; }
set
{
if (_Companies != value)
{
_Companies = value;
RaisePropertyChanged(GetPropertyName(() => Companies));
}
}
}
public CompanyMgmtViewModel()
{
this.LoadData();
}
public void LoadData()
{
ObservableCollection<Object> records = new ObservableCollection<Object>();
var results = from res in AODB.Context.TCompanies
select res;
foreach (var item in results)
if (item != null) records.Add(item);
Companies = records;
}
}
The Model/Context code is just EF Database First generated.
You would need to bind your XamDataGrid's SelectedDataItems property to a property of type object[] ie. SelectedCompanies in your ViewModel and bind to that for your XamDataCards' datasource.
The accepted answer in this thread has a sample that shows how to do this, albeit with a ListBox instead of XamDataCards:
http://www.infragistics.com/community/forums/t/89122.aspx
Just replace that ListBox with your XamDataCards control, it works and updates the XamDataGrid. The ViewModel in the example is contained in the MainWindow code-behind, so it is MVVM like you want.
more info:
http://help.infragistics.com/Help/Doc/WPF/2014.1/CLR4.0/html/xamDataGrid_Selected_Data_Items.html
IG's SelectedDataItems is an object[] :
http://help.infragistics.com/Help/Doc/WPF/2014.1/CLR4.0/html/InfragisticsWPF4.DataPresenter.v14.1~Infragistics.Windows.DataPresenter.DataPresenterBase~SelectedDataItems.html
I couldn't have gotten to this answer without Theodosius' and Ganesh's input - so thanks to them, they both had partial answers.
I first tried to bind the SelectedDataItems of the XamDataGrid to the XamDataCards by way of a property on the ViewModel as Theodosius suggested, but that wasn't enough. Thanks to Ganesh, I implemented INotifyPropertyChanged on my model objects, by inheriting from ObservableObject in MVVMLight (how did I not know the Model needed this?).
Below are the relevant pieces of code to make it work.
I also implemented PropertyChanged.Fody as documented here; that's where the TypedViewModelBase<T> and removal of RaisePropertyChanged() comes from.
I'm also creating my Model objects by using a LINQ/Automapper .Project().To<T>() call which can be found here.
Model
public class Company : ObservableObject
{
public Company() { }
public int id { get; set; }
public string strName { get; set; }
public string strDomicileCode { get; set; }
}
ViewModel
public class CompanyMgmtViewModel : TypedViewModelBase<Company>
{
private ObservableCollection<Object> _Companies = null;
private Object[] _selectedCompany = null;
public Object[] Company
{
get { return _selectedCompany; }
set
{
if (_Company != value)
{
_selectedCompany = value;
}
}
}
public ObservableCollection<Object> Companies
{
get { return _Companies; }
set
{
if (_Companies != value)
{
_Companies = value;
}
}
}
public CompanyMgmtViewModel()
{
this.LoadData();
}
public void LoadData()
{
ObservableCollection<Object> records = new ObservableCollection<Object>();
var results = AODB.Context.TCompanies.Project().To<Company>();
foreach (var item in results)
if (item != null) records.Add(item);
Companies = records;
}
}
View
<igDP:XamDataGrid x:Name="dgCompanies"
Theme="IGTheme"
DataSource="{Binding Companies, Mode=OneWay}"
SelectedDataItemsScope="RecordsOnly"
SelectedDataItems="{Binding Company}">
...
<igDP:XamDataCards x:Name="XamDataCards1"
Grid.Row="1"
DataSource="{Binding ElementName=dgCompanies, Path=SelectedDataItems}"
Theme="IGTheme">
I'm having trouble getting my UI to update Two Listboxes' to update properly when my ViewModel changes.
First, the basic logic behind the page:
Movie is an object with a title, and a variety of MovieDetails. Some MovieDetail are different than others, as they are detailed which is a glorified way of saying they're more Important.
I use two ListBoxes to separate these MovieDetails into stacked ListBoxes, one for 'Detailed' and one for 'NotDetailed'
If a movie has no 'Detailed' attributes, the corresponding list is Hidden via a BooleanToVisibilityConverter (and vice-versa)
When I navigate to the page, I set the Movie the page corresponds to, and it should RaisePropertyChanged to alert the AllMoviesDetail ObservableCollection that it should re-get Movies.MovieDetailFetchedList.
From there, AllMoviesDetail would alert the two ObservableCollections (Detailed, NotDetailed) they should be re-get.
In fact, RaisePropertyChanged on NotDetailedMovieDetails or DetailedMovieDetails does not seem to do anything either. (And the corresponding HasNotDetailedMovieDetails, Has...)
What does work, however, is if I add more items into the list, the CollectionChanged event seems to fire and reactivate the list. I have also been able to do this by instantiating the ObservableCollections in code first var temp = DetailedMoviesDetail;
public class MoviesDetailViewModel : ViewModelBase
{
#region Property Names
public const string MoviePropertyString = "Movie";
public const string AllMoviesDetailPropertyString = "AllMoviesDetail";
public const string DetailedMoviesDetailPropertyString = "DetailedMoviesDetail";
public const string NotDetailedMoviesDetailPropertyString = "NotDetailedMoviesDetail";
public const string HasNotDetailedMoviesDetailPropertyString = "HasNotDetailedMoviesDetail";
public const string HasDetailedMoviesDetailPropertyString = "HasDetailedMoviesDetail";
public const string NotDetailedHeaderPropertyString = "NotDetailedHeader";
#endregion
public MoviesDetailViewModel()
{
if (IsInDesignMode)
{
Movie = DesignDataStore.MovieList[0];
Movie.Category = Category.DDA;
}
}
private Movie _Movie;
/// <summary>
/// The Movie for which to browse MoviesDetail. It is expected when setting this property, that MoviesDetail for it have been downloaded previously.
/// </summary>
/// <remarks>The 'Master' property for this ViewModel. All properties are Dependent on this and the underlying property MoviesDetailList</remarks>
/// <seealso cref="MovieDetailFetchedList"/>
public Movie Movie
{
get { return _Movie; }
set
{
if (_Movie != value)
{
if (_Movie != null)
_Movie.MovieDetailFetchedList.CollectionChanged -= MoviesDetailListChanged;
_Movie = value;
RaisePropertyChanged(MoviePropertyString);
RaisePropertyChanged(StatementPeriodAvailablePropertyString);
RaisePropertyChanged(NotDetailedMoviesDetailPropertyString);
Movie.MovieDetailFetchedList.CollectionChanged += MoviesDetailListChanged;
RaisePropertyChanged(AllMoviesDetailPropertyString);
RaisePropertyChanged(DetailedMoviesDetailPropertyString);
RaisePropertyChanged(NotDetailedHeaderPropertyString);
}
}
}
private void MoviesDetailListChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.Action == NotifyCollectionChangedAction.Add)
{
foreach (var item in e.NewItems)
{
if (((MovieDetail) item).IsDetailed())
DetailedMoviesDetail.Add(item as MovieDetail);
else
NotDetailedMoviesDetail.Add(item as MovieDetail);
}
}
else
{
RaisePropertyChanged(AllMoviesDetailPropertyString);
RaisePropertyChanged(DetailedMoviesDetailPropertyString);
RaisePropertyChanged(NotDetailedMoviesDetailPropertyString);
}
}
#endregion
private MovieDetailFetchedList _allMoviesDetail;
public MovieDetailFetchedList AllMoviesDetail
{
get
{
if (Movie == null)
return new MovieDetailFetchedList();
return _allMoviesDetail ?? (AllMoviesDetail = Movie.MovieDetailFetchedList);
}
set
{
if (_allMoviesDetail != value)
{
if (_allMoviesDetail != null)
_allMoviesDetail.CollectionChanged -= MoviesDetailListChanged;
_allMoviesDetail = value;
_allMoviesDetail.CollectionChanged += MoviesDetailListChanged;
RaisePropertyChanged(AllMoviesDetailPropertyString);
//force update
DetailedMoviesDetail = NotDetailedMoviesDetail = null;
RaisePropertyChanged(DetailedMoviesDetailPropertyString);
RaisePropertyChanged(HasDetailedMoviesDetailPropertyString);
RaisePropertyChanged(NotDetailedMoviesDetailPropertyString);
RaisePropertyChanged(HasNotDetailedMoviesDetailPropertyString);
}
}
}
public bool HasNotDetailedMoviesDetail { get { return NotDetailedMoviesDetail != null && NotDetailedMoviesDetail.Count > 0; } }
private ObservableCollection<MovieDetail> _notDetailedMoviesDetail;
public ObservableCollection<MovieDetail> NotDetailedMoviesDetail
{
get
{
if (Movie == null) return new ObservableCollection<MovieDetail>();
return AllMoviesDetail;
return _notDetailedMoviesDetail ?? //make sure RaisePropertyChanged happens by using property setter
(NotDetailedMoviesDetail = AllMoviesDetail.Where(mem => !mem.IsDetailed()).ToObservableCollection());
}
set
{
_notDetailedMoviesDetail = value;
RaisePropertyChanged(NotDetailedMoviesDetailPropertyString);
RaisePropertyChanged(HasNotDetailedMoviesDetailPropertyString);
}
}
public bool HasDetailedMoviesDetail
{ get { return DetailedMoviesDetail != null && DetailedMoviesDetail.Count > 0; } }
private ObservableCollection<MovieDetail> _DetailedMoviesDetail;
public ObservableCollection<MovieDetail> DetailedMoviesDetail
{
get
{
if (Movie == null) return new ObservableCollection<MovieDetail>();
return AllMoviesDetail;
return _DetailedMoviesDetail ?? //make sure RaisePropertyChanged happens by using property setter
(DetailedMoviesDetail = AllMoviesDetail.Where(mem => mem.IsDetailed()).ToObservableCollection());
}
set
{
_DetailedMoviesDetail = value;
RaisePropertyChanged(DetailedMoviesDetailPropertyString);
RaisePropertyChanged(HasDetailedMoviesDetailPropertyString);
}
}
private string _DetailedHeader;
public string DetailedHeader
{
get { return _DetailedHeader ?? (_DetailedHeader = AppResources.in_available); }
set { _DetailedHeader = value; }
}
public string NotDetailedHeader
{
get { return (Movie != null && Movie.Category == Category.DRAMA) ? AppResources.Movie_MoviesDetail : AppResources.not_in_available; }
}
}
All of your property getters (except AllMoviesDetail) have two return statements. Since only the first will be executed, the values are not being assigned and the PropertyChanged events are not being twiggered.