inotifypropertychanged

问题 I have a class as follows: class Foo : PropertyChangedBase { private int _property; public int Property { get { return _property; } set { OnAssignPropertyChanged("Property", () => _property, value); } } PropertyChangedBase implements INotifyPropertyChanged with the following methods: protected void OnAssignmentPropertyChanged<T>(string propertyName, Expression<Func<T>> fieldExpression, T value) { var get = fieldExpression.Compile(); if (get().Equals(value)) { return; } // invoke set property

问题 I have the Contact class that implements the INotifyPropertyChanged: public class Contact : INotifyPropertyChanged { public Contact(Contact contact) { this.Username = contact.Username; this.GUID = contact.GUID; this.Msg = contact.Msg; this.Ring = contact.Ring; } private string username; public string Username { get { return username; } set { username = value; NotifyPropertyChanged(nameof(Username)); } } public Guid GUID { get; set; } public bool Msg { get; set; } private bool ring; public

问题 I was never sure about the meaning of propertyName when implementing INotifyPropertyChanged . So generally you implement INotifyPropertyChanged as: public class Data : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName = "") { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); private string itsID; public string ID { get { return itsID; } set { if (itsID != value

问题 I have a class FormItem which implements an IDictionary<string, object> , when I bind the Value property of the FormItem , the PropertyChanged event is always null, but when I remove the IDictionary from FormItem then the FormItem.PropertyChanged event is not null. I want to know why it is null when I am implementing IDictionary and how it can be fixed. Example public class FormItem : INotifyPropertyChanged, IDictionary<string, object> { public int _value; public int Value { get { return

问题 I find myself a bit lost on this one. I honestly can't see the error if it's just a class structure doesn't match JSON error. But I doubt it since it's the very same class structure I'm using to create the JSON. If anyone can point me in the right direction, I'd be most greateful. I've created a dotnetfiddle to avoid clutching the question with huge pieces of code. Here's the link: Fiddle I generate that JSON with a console application that gets info on the DB schema. I use a common project

问题 I have a data bound UI. When I change the underlying data the UI updates fine but the controls appear to remain subscribed to my PropertyChanged events. I have the following: An ItemsControl bound to ListA Each item ListA contains a sub list ListB that is displayed using another ItemsControl Each item ListB is displayed using a TextBox bound to a string property via INotifyPropertyChanged Here is the XAML: <UserControl x:Class="SilverlightBindingTest.MainPage" xmlns="http://schemas.microsoft

问题 I have several custom calculated properties on an EntityObject. I would like to fire the PropertyChanged event to notify all bindings. This does not work however, and it throws an argumentexception when I use ReportPropertyChanged: De eigenschap Name heeft geen geldige entiteitstoewijzing op het entiteitsobject. Zie de documentatie van Entity Framework voor meer informatie. Which means than Name is not an entity property and I should look in the Entity Framework documentation for more

问题 I have a class that is bound to a ListBox: class FolderFM : INotifyPropertyChanged { public FolderFM(string path) { this.Folder = new DirectoryInfo(path); this.Name = Folder.Name; } private string name; private DirectoryInfo folder; private ObservableCollection<FileInfo> matchingFiles; ... public ObservableCollection<FileInfo> MatchingFiles { get { return matchingFiles; } set { matchingFiles = value; FireWhenPropertyChanged("MatchingFiles"); } } public event PropertyChangedEventHandler

问题 I have a listbox which is databound to a collection of objects. I want to modify the way the items are displayed to show the user which one of these objects is the START object in my program. I tried to do this the following way, but the listbox does not automatically update. Invalidating the control also didn't work. The only way I can find is to completely remove the databindings and add it back again. but in my case that is not desirable. Is there another way? class Person :

问题 I know how to Bind to Count, but how do I do it, if I only want the count where type is Product <TextBlock Text="{Binding Items.Count}" /> Items = new ObservableCollection<object>(); I tried with a Property, But I am having problem keeping it in sync when Items are being added or removed. public int ProductCount { get { return Items.Cast<object>().Count(item => item.GetType() == typeof (ProductViewModel)); } } 回答1: Additional to getting the correct number of items matching the type you have