using System;

using System.ComponentModel;

using System.Collections.Generic;

using System.Diagnostics;

using System.Reflection;

namespace Equin.ApplicationFramework

{

/// <summary>

/// Serves a wrapper for items being viewed in a <see cref="BindingListView&lt;T&gt;"/>.

/// This class implements <see cref="INotifyEditableObject"/> so will raise the necessary events during

/// the item edit life-cycle.

/// </summary>

/// <remarks>

/// If <typeparamref name="T"/> implements <see cref="System.ComponentModel.IEditableObject"/> this class will call BeginEdit/CancelEdit/EndEdit on the <typeparamref name="T"/> object as well.

/// If <typeparamref name="T"/> implements <see cref="System.ComponentModel.IDataErrorInfo"/> this class will use that implementation as its own.

/// </remarks>

/// <typeparam name="T">The type of object being viewed.</typeparam>

[Serializable]

public class ObjectView<T> : INotifyingEditableObject, IDataErrorInfo, INotifyPropertyChanged, ICustomTypeDescriptor

{

/// <summary>

/// Creates a new <see cref="ObjectView&ltT&gt;"/> wrapper for a <typeparamref name="T"/> object.

/// </summary>

/// <param name="object">The <typeparamref name="T"/> object being wrapped.</param>

public ObjectView(T @object, AggregateBindingListView<T> parent)

{

_parent = parent;

Object = @object;

if (Object is INotifyPropertyChanged)

{

((INotifyPropertyChanged)Object).PropertyChanged += new PropertyChangedEventHandler(ObjectPropertyChanged);

}

if (typeof(ICustomTypeDescriptor).IsAssignableFrom(typeof(T)))

{

_isCustomTypeDescriptor = true;

_customTypeDescriptor = Object as ICustomTypeDescriptor;

Debug.Assert(_customTypeDescriptor != null);

}

_providedViews = new Dictionary<string, object>();

CreateProvidedViews();

}

/// <summary>

/// The view containing this ObjectView.

/// </summary>

private AggregateBindingListView<T> _parent;

/// <summary>

/// Flag that signals if we are currently editing the object.

/// </summary>

private bool _editing;

/// <summary>

/// The actual object being edited.

/// </summary>

private T _object;

/// <summary>

/// Flag set to true if type of T implements ICustomTypeDescriptor

/// </summary>

private bool _isCustomTypeDescriptor;

/// <summary>

/// Holds the Object pre-casted ICustomTypeDescriptor (if supported).

/// </summary>

private ICustomTypeDescriptor _customTypeDescriptor;

/// <summary>

/// A collection of BindingListView objects, indexed by name, for views auto-provided for any generic IList members.

/// </summary>

private Dictionary<string, object> _providedViews;

/// <summary>

/// Gets the object being edited.

/// </summary>

public T Object

{

get { return _object; }

private set

{

if (value == null)

{

throw new ArgumentNullException("Object", Properties.Resources.ObjectCannotBeNull);

}

_object = value;

}

}

public object GetProvidedView(string name)

{

return _providedViews[name];

}

/// <summary>

/// Casts an ObjectView&lt;T&gt; to a T by getting the wrapped T object.

/// </summary>

/// <param name="eo">The ObjectView&lt;T&gt; to cast to a T</param>

/// <returns>The object that is wrapped.</returns>

public static explicit operator T(ObjectView<T> eo)

{

return eo.Object;

}

public override bool Equals(object obj)

{

if (obj == null)

{

return false;

}

if (obj is T)

{

return Object.Equals(obj);

}

else if (obj is ObjectView<T>)

{

return Object.Equals((obj as ObjectView<T>).Object);

}

else

{

return base.Equals(obj);

}

}

public override int GetHashCode()

{

return Object.GetHashCode();

}

public override string ToString()

{

return Object.ToString();

}

private void ObjectPropertyChanged(object sender, PropertyChangedEventArgs e)

{

// Raise our own event

OnPropertyChanged(sender, new PropertyChangedEventArgs(e.PropertyName));

}

private bool ShouldProvideViewOf(PropertyDescriptor listProp)

{

return _parent.ShouldProvideView(listProp);

}

private string GetProvidedViewName(PropertyDescriptor listProp)

{

return _parent.GetProvidedViewName(listProp);

}

private void CreateProvidedViews()

{

foreach (PropertyDescriptor prop in (this as ICustomTypeDescriptor).GetProperties())

{

if (ShouldProvideViewOf(prop))

{

object view = _parent.CreateProvidedView(this, prop);

string viewName = GetProvidedViewName(prop);

_providedViews.Add(viewName, view);

}

}

}

#region INotifyEditableObject Members

/// <summary>

/// Indicates an edit has just begun.

/// </summary>

[field: NonSerialized]

public event EventHandler EditBegun;

/// <summary>

/// Indicates the edit was cancelled.

/// </summary>

[field: NonSerialized]

public event EventHandler EditCancelled;

/// <summary>

/// Indicated the edit was ended.

/// </summary>

[field: NonSerialized]

public event EventHandler EditEnded;

protected virtual void OnEditBegun()

{

if (EditBegun != null)

{

EditBegun(this, EventArgs.Empty);

}

}

protected virtual void OnEditCancelled()

{

if (EditCancelled != null)

{

EditCancelled(this, EventArgs.Empty);

}

}

protected virtual void OnEditEnded()

{

if (EditEnded != null)

{

EditEnded(this, EventArgs.Empty);

}

}

#endregion

#region IEditableObject Members

public void BeginEdit()

{

// As per documentation, this method may get called multiple times for a single edit.

// So we set a flag to only honor the first call.

if (!_editing)

{

_editing = true;

// If possible call the object's BeginEdit() method

// to let it do what ever it needs e.g. save state

if (Object is IEditableObject)

{

((IEditableObject)Object).BeginEdit();

}

// Raise the EditBegun event.

OnEditBegun();

}

}

public void CancelEdit()

{

// We can only cancel if currently editing

if (_editing)

{

// If possible call the object's CancelEdit() method

// to let it do what ever it needs e.g. rollback state

if (Object is IEditableObject)

{

((IEditableObject)Object).CancelEdit();

}

// Raise the EditCancelled event.

OnEditCancelled();

// No longer editing now.

_editing = false;

}

}

public void EndEdit()

{

// We can only end if currently editing

if (_editing)

{

// If possible call the object's EndEdit() method

// to let it do what ever it needs e.g. commit state

if (Object is IEditableObject)

{

((IEditableObject)Object).EndEdit();

}

// Raise the EditEnded event.

OnEditEnded();

// No longer editing now.

_editing = false;

}

}

#endregion

#region IDataErrorInfo Members

// If the wrapped Object support IDataErrorInfo we forward calls to it.

// Otherwise, we just return empty strings that signal "no error".

string IDataErrorInfo.Error

{

get

{

if (Object is IDataErrorInfo)

{

return ((IDataErrorInfo)Object).Error;

}

return string.Empty;

}

}

string IDataErrorInfo.this[string columnName]

{

get

{

if (Object is IDataErrorInfo)

{

return ((IDataErrorInfo)Object)[columnName];

}

return string.Empty;

}

}

#endregion

#region INotifyPropertyChanged Members

[field: NonSerialized]

public event PropertyChangedEventHandler PropertyChanged;

protected virtual void OnPropertyChanged(object sender, PropertyChangedEventArgs args)

{

if (PropertyChanged != null)

{

PropertyChanged(sender, args);

}

}

#endregion

#region ICustomTypeDescriptor Members

AttributeCollection ICustomTypeDescriptor.GetAttributes()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetAttributes();

}

else

{

return TypeDescriptor.GetAttributes(Object);

}

}

string ICustomTypeDescriptor.GetClassName()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetClassName();

}

else

{

return typeof(T).FullName;

}

}

string ICustomTypeDescriptor.GetComponentName()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetComponentName();

}

else

{

return TypeDescriptor.GetFullComponentName(Object);

}

}

TypeConverter ICustomTypeDescriptor.GetConverter()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetConverter();

}

else

{

return TypeDescriptor.GetConverter(Object);

}

}

EventDescriptor ICustomTypeDescriptor.GetDefaultEvent()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetDefaultEvent();

}

else

{

return TypeDescriptor.GetDefaultEvent(Object);

}

}

PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetDefaultProperty();

}

else

{

return TypeDescriptor.GetDefaultProperty(Object);

}

}

object ICustomTypeDescriptor.GetEditor(Type editorBaseType)

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetEditor(editorBaseType);

}

else

{

return null;

}

}

EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes)

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetEvents();

}

else

{

return TypeDescriptor.GetEvents(Object, attributes);

}

}

EventDescriptorCollection ICustomTypeDescriptor.GetEvents()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetEvents();

}

else

{

return TypeDescriptor.GetEvents(Object);

}

}

PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes)

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetProperties();

}

else

{

return TypeDescriptor.GetProperties(Object, attributes);

}

}

PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties()

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetProperties();

}

else

{

return TypeDescriptor.GetProperties(Object);

}

}

object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd)

{

if (_isCustomTypeDescriptor)

{

return _customTypeDescriptor.GetPropertyOwner(pd);

}

else

{

return Object;

}

}

#endregion

}

}