Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="IViewModel.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   View model interface.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.ComponentModel;

namespace Catel.MVVM
{
	/// <summary>
	/// View model interface.
	/// </summary>
	public interface IViewModel : INotifyPropertyChanged
	{
		#region Properties
        /// <summary>
        /// Gets a value indicating whether the view model is initialized.
        /// </summary>
        /// <value>
        /// 	<c>true</c> if the view model is initialized; otherwise, <c>false</c>.
        /// </value>
	    bool IsInitialized { get; }

		/// <summary>
		/// Gets a value indicating whether this instance has errors.
		/// </summary>
		/// <value>
		/// 	<c>true</c> if this instance has errors; otherwise, <c>false</c>.
		/// </value>
		bool HasErrors { get; }

		/// <summary>
		/// Gets the title of the view model.
		/// </summary>
		/// <value>The title.</value>
		string Title { get; }
		#endregion

        #region Events
        /// <summary>
        /// Occurs when the view model is about the be saved.
        /// </summary>
        event EventHandler<EventArgs> Saving;

        /// <summary>
        /// Occurs when the view model is saved successfully.
        /// </summary>
        event EventHandler<EventArgs> Saved;

        /// <summary>
        /// Occurs when the view model is about to be canceled.
        /// </summary>
        event EventHandler<EventArgs> Canceling;

        /// <summary>
        /// Occurrs when the view model is canceled.
        /// </summary>
        event EventHandler<EventArgs> Canceled;

        /// <summary>
        /// Occurs when the view model is being closed.
        /// </summary>
        event EventHandler<EventArgs> Closed;
        #endregion

        #region Methods
        /// <summary>
		/// Initializes the data.
		/// </summary>
		void Initialize();

		/// <summary>
		/// Validates the data.
		/// </summary>
		/// <returns>
		/// 	<c>true</c> if validation succeeds; otherwise <c>false</c>.
		/// </returns>
		bool Validate();

		/// <summary>
		/// Validates the specified notify changed properties only.
		/// </summary>
		/// <param name="force">if set to <c>true</c>, a validation is forced (even if the object knows it is already validated).</param>
		/// <param name="notifyChangedPropertiesOnly">if set to <c>true</c> only the properties for which the warnings or errors have been changed
		/// will be updated via <see cref="INotifyPropertyChanged.PropertyChanged"/>; otherwise all the properties that
		/// had warnings or errors but not anymore and properties still containing warnings or errors will be updated.</param>
		/// <returns>
		/// 	<c>true</c> if validation succeeds; otherwise <c>false</c>.
		/// </returns>
		/// <remarks>
		/// This method is useful when the view model is initialized before the window, and therefore WPF does not update the errors and warnings.
		/// </remarks>
		bool Validate(bool force, bool notifyChangedPropertiesOnly);

		/// <summary>
		/// Cancels the editing of the data.
		/// </summary>
		void Cancel();

		/// <summary>
		/// Cancels the editing of the data, but also closes the view model in the same call.
		/// </summary>
		void CancelAndClose();

		/// <summary>
		/// Saves the data.
		/// </summary>
		/// <returns>
		/// 	<c>true</c> if successful; otherwise <c>false</c>.
		/// </returns>
		bool Save();

		/// <summary>
		/// Saves the data, but also closes the view model in the same call if the save succeeds.
		/// </summary>
		/// <returns>
		/// 	<c>true</c> if successful; otherwise <c>false</c>.
		/// </returns>
		bool SaveAndClose();

		/// <summary>
		/// Closes this instance. Always called after the <see cref="Cancel"/> of <see cref="Save"/> method.
		/// </summary>
		void Close();
		#endregion
	}
}