Calculated Properties using Partial Classes(WPF) - wpf

I am trying to use the calculated columns to display in my grid.
I have a partial class automatically generated by EF code generator with three properties:
Here is my code generated by EF entity generator
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Globalization;
using System.Runtime.Serialization;
using System.ComponentModel.DataAnnotations;
namespace Employees.Contract
{
[DataContract(IsReference = true)]
[KnownType(typeof(Department))]
[KnownType(typeof(PropertyType))]
public partial class Employee: IObjectWithChangeTracker, INotifyPropertyChanged,IDataErrorInfo
{
[NonSerialized]
private CLOS.Contract.Validation.DataErrorInfoSupport dataErrorInfoSupport;
public Employee()
{
dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
Init();
}
partial void Init();
string IDataErrorInfo.Error { get { return dataErrorInfoSupport.Error; } }
string IDataErrorInfo.this[string memberName] { get { return dataErrorInfoSupport[memberName]; } }
#region Primitive Properties
[DataMember]
public Nullable<decimal> Salary
{
get { return _salary; }
set
{
if (_salary != value)
{
_salary = value;
OnPropertyChanged("Salary");
}
}
}
private Nullable<decimal> _salary;
[DataMember]
public Nullable<decimal> WageRate
{
get { return _wageRate; }
set
{
if (_wageRate != value)
{
_wageRate = value;
OnPropertyChanged("WageRate");
}
}
}
private Nullable<decimal> _wageRate;
[DataMember]
public Nullable<decimal> Bonus
{
get { return _bonus; }
set
{
if (_bonus != value)
{
_bonus = value;
OnPropertyChanged("Bonus");
}
}
}
private Nullable<decimal> _bonus;
#endregion
#region Navigation Properties
[DataMember]
public Department Department
{
get { return _department; }
set
{
if (!ReferenceEquals(_department, value))
{
var previousValue = _department;
_department = value;
OnNavigationPropertyChanged("Department");
}
}
}
private Borrower _department;
[DataMember]
public PropertyType PropertyType
{
get { return _propertyType; }
set
{
if (!ReferenceEquals(_propertyType, value))
{
var previousValue = _propertyType;
_propertyType = value;
OnNavigationPropertyChanged("PropertyType");
}
}
}
private PropertyType _propertyType;
#endregion
#region ChangeTracking
protected virtual void OnPropertyChanged(String propertyName)
{
if (ChangeTracker.State != ObjectState.Added && ChangeTracker.State != ObjectState.Deleted)
{
ChangeTracker.State = ObjectState.Modified;
}
if (_propertyChanged != null)
{
_propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
protected virtual void OnNavigationPropertyChanged(String propertyName)
{
if (_propertyChanged != null)
{
_propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged{ add { _propertyChanged += value; } remove { _propertyChanged -= value; } }
private event PropertyChangedEventHandler _propertyChanged;
private ObjectChangeTracker _changeTracker;
[DataMember]
public ObjectChangeTracker ChangeTracker
{
get
{
if (_changeTracker == null)
{
_changeTracker = new ObjectChangeTracker();
_changeTracker.ObjectStateChanging += HandleObjectStateChanging;
}
return _changeTracker;
}
set
{
if(_changeTracker != null)
{
_changeTracker.ObjectStateChanging -= HandleObjectStateChanging;
}
_changeTracker = value;
if(_changeTracker != null)
{
_changeTracker.ObjectStateChanging += HandleObjectStateChanging;
}
}
}
private void HandleObjectStateChanging(object sender, ObjectStateChangingEventArgs e)
{
if (e.NewState == ObjectState.Deleted)
{
ClearNavigationProperties();
}
}
protected bool IsDeserializing { get; private set; }
[OnDeserializing]
public void OnDeserializingMethod(StreamingContext context)
{
IsDeserializing = true;
}
[OnDeserialized]
public void OnDeserializedMethod(StreamingContext context)
{
dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
IsDeserializing = false;
ChangeTracker.ChangeTrackingEnabled = true;
}
protected virtual void ClearNavigationProperties()
{
Department = null;
PropertyType = null;
}
#endregion
}
}
It also works if i put OnPropertyChanged("Salary") in Hours,Wage,Overtime Property in EF Generated class (which is not a good idea) because if the class gets regenerated , my code will be wiped out
Any help is appreciated. (Sorry for the formatting , this is my first question)
Thanks

Final Draft
(I removed old edits due to irrelevance)
In your partial class add, in addition to your definition of Salary:
partial void Init()
{
_propertyChanged += NotifySalary;
}
private void NotifySalary(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == "Wages" || e.PropertyName == "Hours" || e.PropertyName == "Overtime")
{
OnPropertyChanged("Salary");
}
}

I was able to fix this issue. What was happening is that service was marshaling the data back to the UI but it was not marshaling the events with the properties, so what i had to do was to call the init method from the UI and it started working.

Related

I need your suggestion regarding loop in Model to ViewModel MVVM

I'am new to WPF and MVVM and I was given the task to continue working on one of the unfinished project that is made using the said technology. I've written a sample code below that is similar to the structure of the project.
My concern is, the loop used in GetBookPages() to display the details on the grid might take some time to finish.
public class BookModel
{
public string BookTitle { get; set; }
public List<BookDetailModel> BookDetails { get; set; }
}
public class BookDetailModel
{
public int Pages { get; set; }
public string Others { get; set; }
// ....
}
public class BookViewModel : INotifyPropertyChanged
{
private BookModel _model;
private ObservableCollection<BookDetailViewModel> _bookDetailSource;
private BookService _service;
public BookViewModel()
{
_model = new BookModel();
_service = new BookService();
GetBookPages();
}
/// <summary>
/// This is the item source of datagrid that is located in view
/// </summary>
public ObservableCollection<BookDetailViewModel> BookDetailSource
{
get { return _bookDetailSource; }
set
{
if (value == _bookDetailSource)
return;
_bookDetailSource = value;
OnPropertyChanged();
}
}
private void GetBookPages()
{
BookModel bookModel = _service.GetBookData();
var listOf = new List<BookDetailViewModel>();
bookModel.BookDetails.ForEach(e =>
{
// This is were the system's bottle neck is.
// can someone please suggests me a good work around.
listOf.Add(
new BookDetailViewModel
{
Others = e.Others,
// ....
});
});
BookDetailSource = new ObservableCollection<BookDetailViewModel>(listOf);
}
public string BookTitle
{
get { return _model.BookTitle; }
set
{
if (value == _model.BookTitle)
return;
_model.BookTitle = value;
OnPropertyChanged();
}
}
#region Property Change
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
public class BookDetailViewModel : INotifyPropertyChanged
{
private BookDetailModel _model;
#region Constructor
public BookDetailViewModel()
{
_model = new BookDetailModel();
ViewPageDataCommand = new RelayCommand(x => ViewPageData());
RemovePageCommdand = new RelayCommand(x => RemovePage());
}
#endregion
#region Properties
public int Page
{
get { return _model.Pages; }
set
{
if (value == _model.Pages)
return;
_model.Pages = value;
OnPropertyChanged();
}
}
public string Others
{
get { return _model.Others; }
set
{
if (value == _model.Others)
return;
_model.Others = value;
OnPropertyChanged();
}
}
#endregion
// These are the button command inside the grid's row
public ICommand ViewPageDataCommand { get; private set; }
public ICommand RemovePageCommdand { get; private set; }
private void ViewPageData()
{
// view the page data by clicking the row button inside the grid
}
private void RemovePage()
{
// will remove the currently selected row inside the grid
}
#region Property Change
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
public class BookService
{
public BookModel GetBookData()
{
var data = GetBookData(99);
data.BookDetails = GetBookDetail(99);
return data;
}
private BookModel GetBookData(int bookId)
{
// return 1 row only
}
private List<BookDetailModel> GetBookDetail(int bookId)
{
// return List<BookDetailModel> that might consists of more than 100 index's
}
}
I hope you understand what I mean. Your suggestion will be much appreciated. Thanks in advance!

Again, ObservableCollection doesnt Update item

Thats my first project using MVVM , MVVM light.
I have a listbox, that gets refreshed from the PersonList Observable collection, adding and removing refresh it normal. the problem is when editing an item.
I looked for all the solutions for this problem, nothing worked, which make me think that I missed something.
so here is the code :
public class AdminViewModel : ApplicationPartBaseViewModel
{
private ObservableCollection<Person> personList;
public AdminViewModel()
{
this.context = new Entities();
this.SavePersonCommand = new RelayCommand(() => this.SavePerson ());
this.PersonList = new ObservableCollection<Peson>(context.Person.OrderBy(o => o.PersonName).ToList());
}
public ObservableCollection<Person> PersonList
{
get
{
return personList;
}
set
{
this.personList = value;
RaisePropertyChanged("PersonList");
}
}
private void SavePerson()
{
//Add and update code here
this.context.SaveChanges();
RaisePropertyChanged("PersonList");
}
}
Person Class is Autogenerated template from the DataModel edmx
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
public partial class Person
{
#region Primitive Properties
public virtual int PersonId
{
get;
set;
}
public virtual string PersonName
{
get;
set;
}
public virtual Nullable<int> PersonAge
{
get;
set;
}
#endregion
#region Navigation Properties
public virtual ICollection<Humans> Humans
{
get
{
if (_human == null)
{
var newCollection = new FixupCollection<Human>();
newCollection.CollectionChanged += FixupHuman;
_human = newCollection;
}
return _human;
}
set
{
if (!ReferenceEquals(_human, value))
{
var previousValue = _human as FixupCollection<Human>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupHuman;
}
_human = value;
var newValue = value as FixupCollection<Human>;
if (newValue != null)
{
newValue.CollectionChanged += FixupAssets;
}
}
}
}
private ICollection<Human> _human;
#endregion
#region Association Fixup
private void FixupHuman(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (Human item in e.NewItems)
{
if (!item.Person.Contains(this))
{
item.Person.Add(this);
}
}
}
if (e.OldItems != null)
{
foreach (Human item in e.OldItems)
{
if (item.Person.Contains(this))
{
item.Person.Remove(this);
}
}
}
}
#endregion
}
I thought that MVVM light update the item when I call RaisePropertyChanged.
I am so confused.
Thanks in advance.
First option is try to get your auto-generated class to implement INPC if you can. Have a look at Fody.PropertyChanged
If that's not possible, since it does have it's properties as "virtual", we can over-ride them in a derived class such as
public class ObservablePerson : Person, INotifyPropertyChanged {
public override int PersonId {
get {
return base.PersonId;
}
set {
base.PersonId = value;
OnPropertyChanged();
}
}
public override string PersonName {
get {
return base.PersonName;
}
set {
base.PersonName = value;
OnPropertyChanged();
}
}
public override int? PersonAge {
get {
return base.PersonAge;
}
set {
base.PersonAge = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) {
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
Now in your AdminViewModel work with objects of type ObservablePerson than Person

How to create calculated Fields in Partial Classes - WPF

I am trying to use the calculated columns to display in my grid.
I have a partial class automatically generated by EF code generator with three properties: and i am trying to creating another partial class and add calculated field there for e.g.
Public partial class Employee
{
public decimal? totalSalary
{
get
{
return salary*wagerate+bonus;
}
}
}
It works fine for the first time but does not work when the salary/bonus/hours are changed. I am using these fields inside a grid
Here is my code generated by EF entity generator
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Globalization;
using System.Runtime.Serialization;
using System.ComponentModel.DataAnnotations;
namespace Employees.Contract
{
[DataContract(IsReference = true)]
[KnownType(typeof(Department))]
[KnownType(typeof(PropertyType))]
public partial class Employee: IObjectWithChangeTracker, INotifyPropertyChanged,IDataErrorInfo
{
[NonSerialized]
private CLOS.Contract.Validation.DataErrorInfoSupport dataErrorInfoSupport;
public Employee()
{
dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
Init();
}
partial void Init();
string IDataErrorInfo.Error { get { return dataErrorInfoSupport.Error; } }
string IDataErrorInfo.this[string memberName] { get { return dataErrorInfoSupport[memberName]; } }
#region Primitive Properties
[DataMember]
public Nullable<decimal> Salary
{
get { return _salary; }
set
{
if (_salary != value)
{
_salary = value;
OnPropertyChanged("Salary");
}
}
}
private Nullable<decimal> _salary;
[DataMember]
public Nullable<decimal> WageRate
{
get { return _wageRate; }
set
{
if (_wageRate != value)
{
_wageRate = value;
OnPropertyChanged("WageRate");
}
}
}
private Nullable<decimal> _wageRate;
[DataMember]
public Nullable<decimal> Bonus
{
get { return _bonus; }
set
{
if (_bonus != value)
{
_bonus = value;
OnPropertyChanged("Bonus");
}
}
}
private Nullable<decimal> _bonus;
#endregion
#region Navigation Properties
[DataMember]
public Department Department
{
get { return _department; }
set
{
if (!ReferenceEquals(_department, value))
{
var previousValue = _department;
_department = value;
OnNavigationPropertyChanged("Department");
}
}
}
private Borrower _department;
[DataMember]
public PropertyType PropertyType
{
get { return _propertyType; }
set
{
if (!ReferenceEquals(_propertyType, value))
{
var previousValue = _propertyType;
_propertyType = value;
OnNavigationPropertyChanged("PropertyType");
}
}
}
private PropertyType _propertyType;
#endregion
#region ChangeTracking
protected virtual void OnPropertyChanged(String propertyName)
{
if (ChangeTracker.State != ObjectState.Added && ChangeTracker.State != ObjectState.Deleted)
{
ChangeTracker.State = ObjectState.Modified;
}
if (_propertyChanged != null)
{
_propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
protected virtual void OnNavigationPropertyChanged(String propertyName)
{
if (_propertyChanged != null)
{
_propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged{ add { _propertyChanged += value; } remove { _propertyChanged -= value; } }
private event PropertyChangedEventHandler _propertyChanged;
private ObjectChangeTracker _changeTracker;
[DataMember]
public ObjectChangeTracker ChangeTracker
{
get
{
if (_changeTracker == null)
{
_changeTracker = new ObjectChangeTracker();
_changeTracker.ObjectStateChanging += HandleObjectStateChanging;
}
return _changeTracker;
}
set
{
if(_changeTracker != null)
{
_changeTracker.ObjectStateChanging -= HandleObjectStateChanging;
}
_changeTracker = value;
if(_changeTracker != null)
{
_changeTracker.ObjectStateChanging += HandleObjectStateChanging;
}
}
}
private void HandleObjectStateChanging(object sender, ObjectStateChangingEventArgs e)
{
if (e.NewState == ObjectState.Deleted)
{
ClearNavigationProperties();
}
}
protected bool IsDeserializing { get; private set; }
[OnDeserializing]
public void OnDeserializingMethod(StreamingContext context)
{
IsDeserializing = true;
}
[OnDeserialized]
public void OnDeserializedMethod(StreamingContext context)
{
dataErrorInfoSupport = new CLOS.Contract.Validation.DataErrorInfoSupport(this);
IsDeserializing = false;
ChangeTracker.ChangeTrackingEnabled = true;
}
protected virtual void ClearNavigationProperties()
{
Department = null;
PropertyType = null;
}
#endregion
}
}
It also works if i put OnPropertyChanged("Salary") in Hours,Wage,Overtime Property in EF Generated class (which is not a good idea) because if the class gets regenerated , my code will be wiped out
Any help is appreciated. (Sorry for the formatting , this is my first question)
Thanks
In the partial class use the partial Init method to subscribe to the PropertyChanged event and when either the salary, wagerate or bonus property changes notify clients of the change of the totalSalary.
This way you do not need to modify the generated code. (that is why the Init method is partial).
public partial class Employee
{
partial void Init()
{
_propertyChanged += PropertyChangedHandler;
}
void PropertyChangedHandler(object sender, PropertyChangedEventArgs args)
{
if(args.PropertyName == "salary" ||
args.PropertyName == "wagerate" ||
args.PropertyName == "bonus")
{
OnPropertyChanged("totalSalary");
}
}
public decimal? totalSalary
{
get
{
return salary * wagerate + bonus;
}
}
}
this is why MVVM is a popular design pattern, if you wrap your Employee (a Model) in a new class (a ViewModel), it will be easier to customise before you hand it to the grid (the View).
However, a hacky way to get your current code working would be to attach to the current PropertyChanged event in your partial class and call OnPropertyChanged("Salary") if the current property name matches one of the dependent properties (watch out for recursion!)

Caliburn Entity DataBinding Funniness

I have a Silverlight application that I am currently working that implements Caliburn.Micro for its MVVM framework. Things are working fine but I am noticing some funniness in some of the binding. What I have is a ShellViewModel and a ShellView that handle the navigation for the application. The ShellViewModel has a list of the loaded ViewModels for the application. The ShellViewModel inherits from Conductor so that it can handle all the activation and deactivation.
I also have a type of ViewModel base class called BaseConductorViewModel that also inherits from Conductor. This is for ViewModel’s that are basically Master-Detail views. For these BaseConductorViewModels I have a BindableCollection called Items. The idea being to bind this collection to a ListBox or other ItemsControl.
When I create an child of this ViewModel and an associated View I have noticed that the ListBox(in this case) only refreshes the binding when I change the ActiveItem at the ShellViewModel level. So when the application initially loads and this view is the default active view you won’t see anything in the list (I am calling Ria service to get the data for this list). But, if I click on another ViewModel on the ShellViewModel/ShellView and then click back it will show the items in the list. This also follows for adding items to the list or removing them. It won’t refresh unless I switch active views. This seems very odd to me and I can’t seem to figure out a way to get it bind as I would except. One more thing to note, when I am adding/removing items; I call the Refresh method, currently I am not using the NotifyOfPropertyChange method though I did try that previously to the same result.
Does anyone have any ideas of what might be going on here? Or any ideas on how I could go about trying to debug this?
Thank you in advance!
Here is the ShellViewModel
public abstract class ShellViewModel<V,M>:Conductor<IViewModel<V, M>>.Collection.OneActive, IViewModelCatalogShell<V,M>
where V:IView
where M:IModel
{
#region Properties/Members
public ViewModelSelectedItemList<V, M> Catalog { get; set; }
#endregion
#region Constructors
public ShellViewModel()
{
Catalog = new ViewModelSelectedItemList<V, M>();
}
#endregion
}
And here is the BaseConductorViewModel
public abstract class BaseConductorViewModel<T,V,M>:Conductor<T>, IViewModel<V, M>
where V:IView
where M:IModel
{
#region Properties/Members
protected Guid _id=Guid.Empty;
public Guid Id
{
get{return _id;}
set
{
_id =value;
NotifyOfPropertyChange("Id");
}
}
protected string _name=string.Empty;
public string Name
{
get { return _name; }
set
{
_name = value;
NotifyOfPropertyChange("Name");
}
}
public string TypeName
{
get
{
return this.GetType().FullName;
}
}
protected string _description = string.Empty;
public string Description
{
get { return _description; }
protected set
{
_description = value;
NotifyOfPropertyChange(() => Description);
}
}
protected V _view;
public V View
{
get { return _view; }
set
{
_view = value;
NotifyOfPropertyChange("View");
}
}
protected M _model;
public M Model
{
get { return _model; }
set
{
_model = value;
NotifyOfPropertyChange("Model");
}
}
protected SelectedItemList<T> _items;
public SelectedItemList<T> Items
{
get { return _items; }
set
{
_items = value;
NotifyOfPropertyChange(() => Items);
}
}
protected Guid _lastModifiedBy = Guid.Empty;
public Guid LastModifiedBy
{
get { return _lastModifiedBy; }
set
{
_lastModifiedBy = value;
NotifyOfPropertyChange("LastModifiedBy");
}
}
protected DateTime _lastModifiedOn = DateTime.Today;
public DateTime LastModifiedOn
{
get { return _lastModifiedOn; }
set
{
_lastModifiedOn = value;
NotifyOfPropertyChange("LastModifiedOn");
}
}
protected string _imageSource = string.Empty;
public string ImageSource
{
get { return _imageSource; }
protected set
{
_imageSource = value;
NotifyOfPropertyChange("ImageSource");
}
}
#endregion
#region Constructors
public BaseConductorViewModel()
{
_items = new SelectedItemList<T>();
Items.SelectItemChanged += new SelectedItemChangedEvent(Items_SelectItemChanged);
Items.SelectedIndexChanged += new SelectedIndexChangedEvent(Items_SelectedIndexChanged);
LoadData();
}
public BaseConductorViewModel(V view, M model)
:this()
{
_items = new SelectedItemList<T>();
View = view;
Model = model;
Items.SelectItemChanged += new SelectedItemChangedEvent(Items_SelectItemChanged);
Items.SelectedIndexChanged += new SelectedIndexChangedEvent(Items_SelectedIndexChanged);
LoadData();
}
#endregion
#region Methods
public abstract void LoadData();
#endregion
#region Event Handlers
private void Items_SelectItemChanged()
{
ChangeActiveItem(Items.SelectedItem, true);
OnActiveItemChanged();
}
private void Items_SelectedIndexChanged(int index)
{
ChangeActiveItem(Items.SelectedItem, true);
OnActiveItemChanged();
}
#endregion
}
The ViewModelSelectedItemList is just a typed version of this class
public class SelectedItemList<T>:IObservableCollection<T>
{
#region Properties/Members
protected BindableCollection<T> _items = new BindableCollection<T>();
protected bool _isReadOnly = false;
protected bool _isNotifying = true;
public bool IsNotifying
{
get
{
return _isNotifying;
}
set
{
_isNotifying = value;
}
}
public int Count
{
get { return _items.Count; }
}
protected int _selectedIndex = -1;
public int SelectedIndex
{
get { return _selectedIndex; }
set
{
_selectedIndex = value;
NotifyOfPropertyChange("SelectedIndex");
FireSelectedIndexChangedEvent(_selectedIndex);
}
}
public T SelectedItem
{
get
{ return _items[_selectedIndex]; }
set
{
_selectedIndex = _items.IndexOf(value);
NotifyOfPropertyChange("SelectedItem");
FireSelectedItemChangedEvent();
}
}
#endregion
#region Events
public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
public event System.Collections.Specialized.NotifyCollectionChangedEventHandler CollectionChanged;
public event SelectedIndexChangedEvent SelectedIndexChanged;
public event SelectedItemChangedEvent SelectItemChanged;
#endregion
#region Constructors
#endregion
#region Methods
public void AddRange(System.Collections.Generic.IEnumerable<T> items)
{
if (!_isReadOnly)
{
foreach (T item in items)
{
_items.Add(item);
}
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
}
}
public void RemoveRange(System.Collections.Generic.IEnumerable<T> items)
{
if (!_isReadOnly)
{
foreach (T item in items)
{
_items.Remove(item);
}
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
}
}
public int IndexOf(T item)
{
return _items.IndexOf(item);
}
public void Insert(int index, T item)
{
if (!_isReadOnly)
{
_items.Insert(index, item);
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
}
}
public void RemoveAt(int index)
{
if (!_isReadOnly)
{
_items.RemoveAt(index);
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
}
}
public T this[int index]
{
get
{
return _items[index];
}
set
{
_items[index] = value;
}
}
public void Add(T item)
{
if (!_isReadOnly)
{
_items.Add(item);
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
_items.Refresh();
}
if (_items.Count == 1)
{
SelectedIndex = 0;
}
}
}
public bool Remove(T item)
{
if (!_isReadOnly)
{
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
return _items.Remove(item);
}
else
{
return false;
}
}
public void Clear()
{
_items.Clear();
}
public bool Contains(T item)
{
return _items.Contains(item);
}
public void CopyTo(T[] array, int arrayIndex)
{
if (!_isReadOnly)
{
_items.CopyTo(array, arrayIndex);
if (_isNotifying)
{
NotifyOfPropertyChange("Count");
}
}
}
public bool IsReadOnly
{
get { return _isReadOnly; }
}
public void Lock()
{
_isReadOnly = true;
}
public void Unlock()
{
_isReadOnly = false;
}
public System.Collections.Generic.IEnumerator<T> GetEnumerator()
{
return _items.GetEnumerator();
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return _items.GetEnumerator();
}
public void NotifyOfPropertyChange(string propertyName)
{
FirePropertyChangedEvent(propertyName);
}
public void Refresh()
{
_items.Refresh();
}
#region Helper Methods
protected void FirePropertyChangedEvent(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
}
}
protected void FireCollectionChangedEvent(NotifyCollectionChangedAction action)
{
if (CollectionChanged != null)
{
CollectionChanged(this, new System.Collections.Specialized.NotifyCollectionChangedEventArgs(action));
}
}
protected void FireSelectedIndexChangedEvent(int index)
{
if (SelectedIndexChanged != null)
{
SelectedIndexChanged(index);
}
}
protected void FireSelectedItemChangedEvent()
{
if (SelectItemChanged != null)
{
SelectItemChanged();
}
}
#endregion
#endregion
}
Not sure if you're problem has something to do with this, from the docs:
Since all OOTB implementations of IConductor inherit from Screen it
means that they too have a lifecycle and that lifecycle cascades to
whatever items they are conducting. So, if a conductor is deactivated,
it’s ActiveItem will be deactivated as well. If you try to close a
conductor, it’s going to only be able to close if all of the items it
conducts can close. This turns out to be a very powerful feature.
There’s one aspect about this that I’ve noticed frequently trips up
developers. If you activate an item in a conductor that is itself not
active, that item won’t actually be activated until the conductor gets
activated. This makes sense when you think about it, but can
occasionally cause hair pulling.
edit:
I think I see what you're trying to do, a couple questions though:
Your ShellViewModel is
Conductor<IViewModel<V,M>>.Collection.OneActive, when is Catalog
activated? I'd think you'd want to add Catalog to Items, then
Activate it.
With the BaseConductorViewModel, it inherits from Conductor which
inherits from Screen, which gets a reference to it's view when it's
bound. I'm not sure what the View property you add is for.
CM can handle setting the selected item for you. So for a master
detail situation where you have an ItemsControl, CM will set the
SelectedItem and from that you can populate the detail.

MVVM Invoke Method in View (from ControlTemplate via ViewModel)

I would like to know how the following problem can be solved WITHOUT using Event Aggregation. This is for WPF 3.5 SP1, so the CallMethodBehavior is not available.
Simple Scenario: A click on a button inside a ControlTemplate needs to be triggered to the VM. I used CaliburnMicro's ActionMessage which worked fine. Inside the ViewModel I want to trigger a method inside the View, which only starts a custom transition (no real logic). I tried many things, but I did not work out.
I created a Property in my view, which could call the method but I am not able to use Triggers to set a new value for the property, because I can't tell the setter to target a property outside the controltemplate.
So in essence I want to update a Property in the viewmodel and trigger a set-property in the view class. Or if you have any idea how to get around this at all: I am open to new ideas! :D
Regards
Gope
i think the most simple way is to expose an event from your vm and subscribe to it in your view?
i used this for dialogs to send DialogResult from vm
I found a solution I can live with: I ported the CallMethodAction to 3.5 and wrote my own PropertyChangedTrigger. It's pretty simple to call a method inside the view via a PropertyChange in the viewmodel - Kids: don't try this at home. It's only for special scenarios! :D
Find my code below:
usage:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
<i:Interaction.Triggers >
<Framework:PropertyChangedTrigger Binding="{Binding StartTransition}" Value="True">
<Framework:CallMethodAction MethodName="ApplyTransition" />
</Framework:PropertyChangedTrigger>
</i:Interaction.Triggers>
PropertyChangedTrigger:
public class PropertyChangedTrigger : TriggerBase<DependencyObject>
{
public static readonly DependencyProperty BindingProperty = DependencyProperty.Register("Binding", typeof(object), typeof(PropertyChangedTrigger), new PropertyMetadata(new PropertyChangedCallback(OnBindingChanged)));
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value", typeof(object), typeof(PropertyChangedTrigger), new PropertyMetadata(null));
public object Binding
{
get
{
return base.GetValue(BindingProperty);
}
set
{
base.SetValue(BindingProperty, value);
}
}
public object Value
{
get
{
return base.GetValue(ValueProperty);
}
set
{
base.SetValue(ValueProperty, value);
}
}
protected virtual void EvaluateBindingChange(object args)
{
var propertyChangedArgs = (DependencyPropertyChangedEventArgs)args;
string newValue = propertyChangedArgs.NewValue.ToString();
bool equal = string.Equals(newValue, Value.ToString(),StringComparison.InvariantCultureIgnoreCase);
if(equal)
{
InvokeActions(args);
}
}
private static void OnBindingChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
((PropertyChangedTrigger)sender).EvaluateBindingChange(args);
}
}
CallMethodAction:
public class CallMethodAction : TargetedTriggerAction<FrameworkElement>
{
private List<MethodDescriptor> methodDescriptors = new List<MethodDescriptor>();
public static readonly DependencyProperty MethodNameProperty = DependencyProperty.Register("MethodName", typeof(string), typeof(CallMethodAction), new PropertyMetadata(new PropertyChangedCallback(OnMethodNameChanged)));
public static readonly DependencyProperty TargetObjectProperty = DependencyProperty.Register("TargetObject", typeof(object), typeof(CallMethodAction), new PropertyMetadata(new PropertyChangedCallback(OnTargetObjectChanged)));
protected override void OnAttached()
{
base.OnAttached();
this.UpdateMethodInfo();
}
protected override void OnDetaching()
{
this.methodDescriptors.Clear();
base.OnDetaching();
}
private static void OnMethodNameChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
((CallMethodAction)sender).UpdateMethodInfo();
}
private static void OnTargetObjectChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
((CallMethodAction)sender).UpdateMethodInfo();
}
private static bool AreMethodParamsValid(ParameterInfo[] methodParams)
{
if (methodParams.Length == 2)
{
if (methodParams[0].ParameterType != typeof(object))
{
return false;
}
if (!typeof(EventArgs).IsAssignableFrom(methodParams[1].ParameterType))
{
return false;
}
}
else if (methodParams.Length != 0)
{
return false;
}
return true;
}
protected override void Invoke(object parameter)
{
if (base.AssociatedObject != null)
{
MethodDescriptor descriptor = this.FindBestMethod(parameter);
if (descriptor != null)
{
ParameterInfo[] parameters = descriptor.Parameters;
if (parameters.Length == 0)
{
descriptor.MethodInfo.Invoke(this.Target, null);
}
else if ((((parameters.Length == 2) && (base.AssociatedObject != null)) && ((parameter != null) && parameters[0].ParameterType.IsAssignableFrom(base.AssociatedObject.GetType()))) && parameters[1].ParameterType.IsAssignableFrom(parameter.GetType()))
{
descriptor.MethodInfo.Invoke(this.Target, new object[] { base.AssociatedObject, parameter });
}
}
else if (this.TargetObject != null)
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "No valid method found.", new object[] { this.MethodName, this.TargetObject.GetType().Name }));
}
}
}
private MethodDescriptor FindBestMethod(object parameter)
{
if (parameter != null)
{
parameter.GetType();
}
return this.methodDescriptors.FirstOrDefault(methodDescriptor => (!methodDescriptor.HasParameters || ((parameter != null) && methodDescriptor.SecondParameterType.IsAssignableFrom(parameter.GetType()))));
}
private void UpdateMethodInfo()
{
this.methodDescriptors.Clear();
if ((this.Target != null) && !string.IsNullOrEmpty(this.MethodName))
{
foreach (MethodInfo info in this.Target.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance))
{
if (this.IsMethodValid(info))
{
ParameterInfo[] parameters = info.GetParameters();
if (AreMethodParamsValid(parameters))
{
this.methodDescriptors.Add(new MethodDescriptor(info, parameters));
}
}
}
this.methodDescriptors = this.methodDescriptors.OrderByDescending<MethodDescriptor, int>(delegate(MethodDescriptor methodDescriptor)
{
int num = 0;
if (methodDescriptor.HasParameters)
{
for (Type type = methodDescriptor.SecondParameterType; type != typeof(EventArgs); type = type.BaseType)
{
num++;
}
}
return (methodDescriptor.ParameterCount + num);
}).ToList<MethodDescriptor>();
}
}
private bool IsMethodValid(MethodInfo method)
{
if (!string.Equals(method.Name, this.MethodName, StringComparison.Ordinal))
{
return false;
}
if (method.ReturnType != typeof(void))
{
return false;
}
return true;
}
public void InvokeInternal()
{
if (AssociatedObject != null)
{
foreach (
MethodInfo info in AssociatedObject.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance))
{
if (IsMethodValid(info))
{
info.Invoke(AssociatedObject, new object[0]);
}
}
}
}
public string MethodName
{
get
{
return (string)base.GetValue(MethodNameProperty);
}
set
{
base.SetValue(MethodNameProperty, value);
}
}
private object Target
{
get
{
return (TargetObject ?? base.AssociatedObject);
}
}
public object TargetObject
{
get
{
return base.GetValue(TargetObjectProperty);
}
set
{
base.SetValue(TargetObjectProperty, value);
}
}
private class MethodDescriptor
{
public MethodDescriptor(MethodInfo methodInfo, ParameterInfo[] methodParams)
{
MethodInfo = methodInfo;
Parameters = methodParams;
}
public bool HasParameters
{
get
{
return (Parameters.Length > 0);
}
}
public MethodInfo MethodInfo { get; private set; }
public int ParameterCount
{
get
{
return Parameters.Length;
}
}
public ParameterInfo[] Parameters { get; private set; }
public Type SecondParameterType
{
get
{
if (Parameters.Length >= 2)
{
return Parameters[1].ParameterType;
}
return null;
}
}
}
}
Hope this helps anybode. All questions are welcome! Remeber: all this can be found in the Expression Blend SDK 4. This code is only for people who are forced to work with older versions like 3.5
Regards
Gope
Gope

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