public void GetInitializedAndSet_EventHandler_AttachedAndDetached()
{
var viewModel1 = new ViewModel { Value = "a" };
var viewModel2 = new ViewModel { Value = "r" };
var counter1 = 0;
var counter2 = 0;
var backingFileds = new BackingFields(
s =>
{
if (s == "ViewModelProperty")
{
counter1++;
}
});
PropertyChangedEventHandler handler = (source, args) =>
{
if (args.PropertyName == "Value")
{
counter2++;
}
};
backingFileds.GetValueAndObserve(() => ViewModelProperty, () => viewModel1, handler);
Assert.AreEqual(0, counter1);
Assert.AreEqual(0, counter2);
viewModel1.Value = "b";
Assert.AreEqual(0, counter1);
Assert.AreEqual(1, counter2);
backingFileds.SetValueAndObserve(() => ViewModelProperty, viewModel2, handler);
Assert.AreEqual(1, counter1);
Assert.AreEqual(1, counter2);
viewModel1.Value = "c";
Assert.AreEqual(1, counter1);
Assert.AreEqual(1, counter2);
viewModel2.Value = "s";
Assert.AreEqual(1, counter1);
Assert.AreEqual(2, counter2);
}
public void GetInitializedAndSet_Observer_AttachedAndDetached()
{
var viewModel1 = new ViewModel { Value = "a" };
var viewModel2 = new ViewModel { Value = "r" };
var counter = 0;
var backingFileds = new BackingFields(
s =>
{
if (s == "ViewModelProperty")
{
counter++;
}
});
backingFileds.GetValueAndObserve(() => ViewModelProperty, () => viewModel1);
Assert.AreEqual(0, counter);
viewModel1.Value = "b";
Assert.AreEqual(1, counter);
backingFileds.SetValueAndObserve(() => ViewModelProperty, viewModel2);
Assert.AreEqual(2, counter);
viewModel1.Value = "c";
Assert.AreEqual(2, counter);
viewModel2.Value = "s";
Assert.AreEqual(3, counter);
}
