//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation. All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious. No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using System.Windows;
using Microsoft.Practices.Composite.Presentation.Properties;
using Microsoft.Practices.Composite.Regions;
namespace Microsoft.Practices.Composite.Presentation.Regions
{
/// <summary>
/// Implementation of <see cref="IRegion"/> that allows multiple active views.
/// </summary>
public class Region : IRegion
{
private ObservableCollection<ItemMetadata> itemMetadataCollection;
private string name;
private IViewsCollection views;
private IViewsCollection activeViews;
private object context;
private IRegionManager regionManager;
/// <summary>
/// Initializes a new instance of <see cref="Region"/>.
/// </summary>
public Region()
{
this.Behaviors = new RegionBehaviorCollection(this);
}
/// <summary>
/// Occurs when a property value changes.
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Gets the collection of <see cref="IRegionBehavior"/>s that can extend the behavior of regions.
/// </summary>
public IRegionBehaviorCollection Behaviors { get; private set; }
/// <summary>
/// Gets or sets a context for the region. This value can be used by the user to share context with the views.
/// </summary>
/// <value>The context value to be shared.</value>
public object Context
{
get
{
return this.context;
}
set
{
if (this.context != value)
{
this.context = value;
this.OnPropertyChanged("Context");
}
}
}
/// <summary>
/// Gets the name of the region that uniequely identifies the region within a <see cref="IRegionManager"/>.
/// </summary>
/// <value>The name of the region.</value>
public string Name
{
get
{
return this.name;
}
set
{
if (this.name != null && this.name != value)
{
throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Resources.CannotChangeRegionNameException, this.name));
}
if (string.IsNullOrEmpty(value))
{
throw new ArgumentException(Resources.RegionNameCannotBeEmptyException);
}
this.name = value;
this.OnPropertyChanged("Name");
}
}
/// <summary>
/// Gets a readonly view of the collection of views in the region.
/// </summary>
/// <value>An <see cref="IViewsCollection"/> of all the added views.</value>
public virtual IViewsCollection Views
{
get
{
if (this.views == null)
{
this.views = new ViewsCollection(ItemMetadataCollection, x => true);
}
return this.views;
}
}
/// <summary>
/// Gets a readonly view of the collection of all the active views in the region.
/// </summary>
/// <value>An <see cref="IViewsCollection"/> of all the active views.</value>
public virtual IViewsCollection ActiveViews
{
get
{
if (this.activeViews == null)
{
this.activeViews = new ViewsCollection(ItemMetadataCollection, x => x.IsActive);
}
return this.activeViews;
}
}
/// <summary>
/// Gets or sets the <see cref="IRegionManager"/> that will be passed to the views when adding them to the region, unless the view is added by specifying createRegionManagerScope as <see langword="true" />.
/// </summary>
/// <value>The <see cref="IRegionManager"/> where this <see cref="IRegion"/> is registered.</value>
/// <remarks>This is usually used by implementations of <see cref="IRegionManager"/> and should not be
/// used by the developer explicitely.</remarks>
public IRegionManager RegionManager
{
get
{
return this.regionManager;
}
set
{
if (this.regionManager != value)
{
this.regionManager = value;
this.OnPropertyChanged("RegionManager");
}
}
}
/// <summary>
/// Gets the collection with all the views along with their metadata.
/// </summary>
/// <value>An <see cref="ObservableCollection{T}"/> of <see cref="ItemMetadata"/> with all the added views.</value>
protected virtual ObservableCollection<ItemMetadata> ItemMetadataCollection
{
get
{
if (this.itemMetadataCollection == null)
{
this.itemMetadataCollection = new ObservableCollection<ItemMetadata>();
}
return this.itemMetadataCollection;
}
}
/// <overloads>Adds a new view to the region.</overloads>
/// <summary>
/// Adds a new view to the region.
/// </summary>
/// <param name="view">The view to add.</param>
/// <returns>The <see cref="IRegionManager"/> that is set on the view if it is a <see cref="DependencyObject"/>. It will be the current region manager when using this overload.</returns>
public IRegionManager Add(object view)
{
return this.Add(view, null, false);
}
/// <summary>
/// Adds a new view to the region.
/// </summary>
/// <param name="view">The view to add.</param>
/// <param name="viewName">The name of the view. This can be used to retrieve it later by calling <see cref="IRegion.GetView"/>.</param>
/// <returns>The <see cref="IRegionManager"/> that is set on the view if it is a <see cref="DependencyObject"/>. It will be the current region manager when using this overload.</returns>
public IRegionManager Add(object view, string viewName)
{
if (string.IsNullOrEmpty(viewName))
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Resources.StringCannotBeNullOrEmpty, "viewName"));
}
return this.Add(view, viewName, false);
}
/// <summary>
/// Adds a new view to the region.
/// </summary>
/// <param name="view">The view to add.</param>
/// <param name="viewName">The name of the view. This can be used to retrieve it later by calling <see cref="IRegion.GetView"/>.</param>
/// <param name="createRegionManagerScope">When <see langword="true"/>, the added view will receive a new instance of <see cref="IRegionManager"/>, otherwise it will use the current region manager for this region.</param>
/// <returns>The <see cref="IRegionManager"/> that is set on the view if it is a <see cref="DependencyObject"/>.</returns>
public virtual IRegionManager Add(object view, string viewName, bool createRegionManagerScope)
{
IRegionManager manager = createRegionManagerScope ? this.RegionManager.CreateRegionManager() : this.RegionManager;
this.InnerAdd(view, viewName, manager);
return manager;
}
/// <summary>
/// Removes the specified view from the region.
/// </summary>
/// <param name="view">The view to remove.</param>
public virtual void Remove(object view)
{
ItemMetadata itemMetadata = this.GetItemMetadataOrThrow(view);
this.ItemMetadataCollection.Remove(itemMetadata);
DependencyObject dependencyObject = view as DependencyObject;
if (dependencyObject != null && Regions.RegionManager.GetRegionManager(dependencyObject) == this.RegionManager)
{
dependencyObject.ClearValue(Regions.RegionManager.RegionManagerProperty);
}
}
/// <summary>
/// Marks the specified view as active.
/// </summary>
/// <param name="view">The view to activate.</param>
public virtual void Activate(object view)
{
ItemMetadata itemMetadata = this.GetItemMetadataOrThrow(view);
if (!itemMetadata.IsActive)
{
itemMetadata.IsActive = true;
}
}
/// <summary>
/// Marks the specified view as inactive.
/// </summary>
/// <param name="view">The view to deactivate.</param>
public virtual void Deactivate(object view)
{
ItemMetadata itemMetadata = this.GetItemMetadataOrThrow(view);
if (itemMetadata.IsActive)
{
itemMetadata.IsActive = false;
}
}
/// <summary>
/// Returns the view instance that was added to the region using a specific name.
/// </summary>
/// <param name="viewName">The name used when adding the view to the region.</param>
/// <returns>Returns the named view or <see langword="null"/> if the view with <paramref name="viewName"/> does not exist in the current region.</returns>
public virtual object GetView(string viewName)
{
if (string.IsNullOrEmpty(viewName))
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Resources.StringCannotBeNullOrEmpty, "viewName"));
}
ItemMetadata metadata = this.ItemMetadataCollection.FirstOrDefault(x => x.Name == viewName);
if (metadata != null)
{
return metadata.Item;
}
return null;
}
private void InnerAdd(object view, string viewName, IRegionManager scopedRegionManager)
{
if (this.ItemMetadataCollection.FirstOrDefault(x => x.Item == view) != null)
{
throw new InvalidOperationException(Resources.RegionViewExistsException);
}
ItemMetadata itemMetadata = new ItemMetadata(view);
if (!string.IsNullOrEmpty(viewName))
{
if (this.ItemMetadataCollection.FirstOrDefault(x => x.Name == viewName) != null)
{
throw new InvalidOperationException(String.Format(CultureInfo.InvariantCulture, Resources.RegionViewNameExistsException, viewName));
}
itemMetadata.Name = viewName;
}
DependencyObject dependencyObject = view as DependencyObject;
if (dependencyObject != null)
{
Regions.RegionManager.SetRegionManager(dependencyObject, scopedRegionManager);
}
this.ItemMetadataCollection.Add(itemMetadata);
}
private ItemMetadata GetItemMetadataOrThrow(object view)
{
if (view == null)
{
throw new ArgumentNullException("view");
}
ItemMetadata itemMetadata = this.ItemMetadataCollection.FirstOrDefault(x => x.Item == view);
if (itemMetadata == null)
{
throw new ArgumentException(Resources.ViewNotInRegionException, "view");
}
return itemMetadata;
}
private void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler eventHandler = this.PropertyChanged;
if (eventHandler != null)
{
eventHandler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}