OnPropertyChanged with strong names

OnPropertyChanged infuriates me wildly. It requires the transfer of the string with the name of the identifier to it ... Not only is such a code not verified by the compiler, so there is no Intellisence - the type is all from beginning to end ... And if you type it, it will swallow it at runtime. In general, not a good thing. But in MVVM without it anywhere, as in WPF without MVVM.



The last problem was somehow solved by such a crutch, stripped from here , which was called from OnPropertyChanged:

[Conditional( "DEBUG" )]

[DebuggerStepThrough]

public void VerifyPropertyName( string propertyName)

{

// Verify that the property name matches a real,

// public, instance property on this object.

if (TypeDescriptor.GetProperties( this )[propertyName] == null )

{

string msg = "Invalid property name: " + propertyName;



if ( this .ThrowOnInvalidPropertyName)

throw new Exception(msg);

else

Debug.Fail(msg);

}

}



And today I accidentally found a beautiful way to get rid of it.



The solution turned out to be beautiful and at the same time simple to the banality: use Expression, like this:

this .OnPropertyChanged(() => this .ShowOverrideButton);



To do this, you just need to create an overload in the base class:

protected void OnPropertyChanged<T>(Expression<Func<T>> property)

{

PropertyChangedEventHandler handler = this .PropertyChanged;

if (handler != null )

{

var expression = property.Body as MemberExpression;

if (expression == null )

{

throw new NotSupportedException( "Invalid expression passed. Only property member should be selected." );

}



handler( this , new PropertyChangedEventArgs(expression.Member.Name));

}

}



* This source code was highlighted with Source Code Highlighter .

Is done. You can forget about the strings in OnPropertyChange. There are still bad lines in XAML in Binding - but I have absolutely no idea how to get rid of them.