Nuclex.Support/Source/Observable.cs

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#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2013 Nuclex Development Labs
This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.
You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion
using System;
using System.ComponentModel;
using System.Diagnostics;
#if !NO_LINQ_EXPRESSIONS
using System.Linq.Expressions;
#endif
using System.Reflection;
namespace Nuclex.Support {
/// <summary>Base class for objects that support property change notifications</summary>
#if !NO_SERIALIZATION
[Serializable]
#endif
public abstract class Observable : INotifyPropertyChanged {
/// <summary>Raised when a property of the instance has changed its value</summary>
#if !NO_SERIALIZATION
[field: NonSerialized]
#endif
public event PropertyChangedEventHandler PropertyChanged;
#if !NO_LINQ_EXPRESSIONS
/// <summary>Triggers the PropertyChanged event for the specified property</summary>
/// <param name="property">
/// Lambda expression for the property that will be reported to have changed
/// </param>
/// <remarks>
/// <para>
/// This notification should be fired post-change, i.e. when the property has
/// already changed its value.
/// </para>
/// <example>
/// <code>
/// public int Limit {
/// get { return this.limit; }
/// set {
/// if(value != this.limit) {
/// this.limit = value;
/// OnPropertyChanged(() => Limit);
/// }
/// }
/// }
/// </code>
/// </example>
/// </remarks>
protected void OnPropertyChanged<TProperty>(Expression<Func<TProperty>> property) {
PropertyChangedEventHandler copy = PropertyChanged;
if(copy != null) {
copy(this, PropertyChangedEventArgsHelper.GetArgumentsFor(property));
}
}
#endif // !NO_LINQ_EXPRESSIONS
/// <summary>Triggers the PropertyChanged event for the specified property</summary>
/// <param name="propertyName">Name of the property that has changed its value</param>
/// <remarks>
/// <para>
/// This notification should be fired post-change, i.e. when the property has
/// already changed its value. If possible, use the other overload of this
/// method to ensure the property name will be updated during F2 refactoring.
/// </para>
/// <example>
/// <code>
/// public int Limit {
/// get { return this.limit; }
/// set {
/// if(value != this.limit) {
/// this.limit = value;
/// OnPropertyChanged("Limit"); // Note: prefer lambda exp whenever possible
/// }
/// }
/// }
/// </code>
/// </example>
/// </remarks>
protected virtual void OnPropertyChanged(string propertyName) {
enforceChangedPropertyExists(propertyName);
PropertyChangedEventHandler copy = PropertyChanged;
if(copy != null) {
copy(this, PropertyChangedEventArgsHelper.GetArgumentsFor(propertyName));
}
}
/// <summary>Ensures that a property with the specified name exists in the type</summary>
/// <param name="propertyName">Property name that will be checked</param>
[Conditional("DEBUG")]
private void enforceChangedPropertyExists(string propertyName) {
// An empty string or null indicates that all properties have changed
if(string.IsNullOrEmpty(propertyName)) {
return;
}
// Any other string needs to match a property name
PropertyInfo property = GetType().GetProperty(propertyName);
if(property == null) {
throw new ArgumentException(
string.Format(
"Type '{0}' tried to raise a change notification for property '{1}', " +
"but no such property exists!",
GetType().Name, propertyName
),
"propertyName"
);
}
}
}
} // namespace Nuclex.Support