/// <summary>
/// Called by View whenever its current View.Model changes. Will locate and instantiate the correct view, and set it as the target's Content
/// </summary>
/// <param name="targetLocation">Thing which View.Model was changed on. Will have its Content set</param>
/// <param name="oldValue">Previous value of View.Model</param>
/// <param name="newValue">New value of View.Model</param>
public virtual void OnModelChanged(DependencyObject targetLocation, object oldValue, object newValue)
{
if (oldValue == newValue)
{
return;
}
if (newValue != null)
{
logger.Info("View.Model changed for {0} from {1} to {2}", targetLocation, oldValue, newValue);
var view = CreateAndBindViewForModelIfNecessary(newValue);
if (view is Window)
{
var e = new StyletInvalidViewTypeException(string.Format("s:View.Model=\"...\" tried to show a View of type '{0}', but that View derives from the Window class. " +
"Make sure any Views you display using s:View.Model=\"...\" do not derive from Window (use UserControl or similar)", view.GetType().Name));
logger.Error(e);
throw e;
}
View.SetContentProperty(targetLocation, view);
}
else
{
logger.Info("View.Model cleared for {0}, from {1}", targetLocation, oldValue);
View.SetContentProperty(targetLocation, null);
}
}
/// <summary>
/// Given a ViewModel, create its View, ensure that it's a Window, and set it up
/// </summary>
/// <param name="viewModel">ViewModel to create the window for</param>
/// <param name="isDialog">True if the window will be used as a dialog</param>
/// <returns>Window which was created and set up</returns>
protected virtual Window CreateWindow(object viewModel, bool isDialog)
{
var view = viewManager.CreateAndBindViewForModelIfNecessary(viewModel);
var window = view as Window;
if (window == null)
{
var e = new StyletInvalidViewTypeException(String.Format("WindowManager.ShowWindow or .ShowDialog tried to show a View of type '{0}', but that View doesn't derive from the Window class. " +
"Make sure any Views you display using WindowManager.ShowWindow or .ShowDialog derive from Window (not UserControl, etc)",
view == null ? "(null)" : view.GetType().Name));
logger.Error(e);
throw e;
}
// Only set this it hasn't been set / bound to anything
var haveDisplayName = viewModel as IHaveDisplayName;
if (haveDisplayName != null && (String.IsNullOrEmpty(window.Title) || window.Title == view.GetType().Name) && BindingOperations.GetBindingBase(window, Window.TitleProperty) == null)
{
var binding = new Binding("DisplayName") { Mode = BindingMode.TwoWay };
window.SetBinding(Window.TitleProperty, binding);
}
if (isDialog)
{
var owner = InferOwnerOf(window);
if (owner != null)
{
// We can end up in a really weird situation if they try and display more than one dialog as the application's closing
// Basically the MainWindow's no long active, so the second dialog chooses the first dialog as its owner... But the first dialog
// hasn't yet been shown, so we get an exception ("cannot set owner property to a Window which has not been previously shown").
try
{
window.Owner = owner;
}
catch (InvalidOperationException e)
{
logger.Error(e, "This can occur when the application is closing down");
}
}
logger.Info("Displaying ViewModel {0} with View {1} as a Dialog", viewModel, window);
}
else
{
logger.Info("Displaying ViewModel {0} with View {1} as a Window", viewModel, window);
}
// If and only if they haven't tried to position the window themselves...
// Has to be done after we're attempted to set the owner
if (window.WindowStartupLocation == WindowStartupLocation.Manual && Double.IsNaN(window.Top) && Double.IsNaN(window.Left))
window.WindowStartupLocation = window.Owner == null ? WindowStartupLocation.CenterScreen : WindowStartupLocation.CenterOwner;
// This gets itself retained by the window, by registering events
// ReSharper disable once ObjectCreationAsStatement
new WindowConductor(window, viewModel);
return window;
}