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Common/DTS.CommonCore/.svn/pristine/78/7867807ab0fcdf0887ce358ba648fa12754ebc2d.svn-base

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+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.IO;
+using System.Threading.Tasks;
+using System.Windows;
+
+// ReSharper disable once CheckNamespace
+namespace DTS.Common.Base
+{
+
+    /// <summary>
+    /// Base class used to create ViewModel objects that implement their own commands/verbs/actions.
+    /// </summary>
+    /// <typeparam name="T">Type of the Model object.</typeparam>
+    public abstract class ViewModelBase<T> : DependencyObject, INotifyPropertyChanged, IViewModel
+    {
+        /// <summary>
+        /// Gets or sets the Model object.
+        /// </summary>
+        public object Model { get; set; }
+
+
+        /// <summary>
+        /// Create new instance of base class used to create ViewModel objects that implement their own commands/verbs/actions.
+        /// </summary>
+        public ViewModelBase()
+        {
+            
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether this object is executing an asynchronous process. 
+        /// </summary>
+        public bool IsBusy { get; protected set; }
+
+        /// <summary>
+        /// Gets a value indicating whether the Model has been changed.
+        /// </summary>
+        public virtual bool IsDirty { get; protected set; }
+    
+
+        // Summary:
+        //     Event raised when an error occurs during processing.
+        /// <summary>
+        /// 
+        /// </summary>
+        public virtual event EventHandler<ErrorEventArgs> ErrorOccurred;
+
+        /// <summary>
+        /// Event raised when a property changes.
+        /// </summary>
+        public virtual event PropertyChangedEventHandler PropertyChanged;
+
+
+        /// <summary>
+        ///     Override this method to implement async initialization of the model object.
+        ///     The result of this method is used to set the Model property of the viewmodel.
+        /// </summary>
+        /// <returns>A Task that creates the model object.</returns>
+        [DebuggerStepThrough]
+        protected abstract Task<T> InitializeAsync();
+
+        /// <summary>
+        /// Creates or retrieves a new instance of the Model by invoking a static factory method.
+        /// </summary>
+        /// <param name="factoryMethod">Static factory method function.</param>
+        protected abstract void DoRefresh(Func<T> factoryMethod);
+
+
+        /// <summary>
+        /// Raises ErrorOccurred event when an error occurs during processing.
+        /// </summary>
+        /// <param name="error"></param>
+        protected abstract void OnError(Exception error);
+        
+        /// <summary>
+        /// Invoked when the Model changes, allowing event handlers to be unhooked from the old object and hooked on the new object.
+        /// </summary>
+        /// <param name="oldValue">Previous Model reference.</param>
+        /// <param name="newValue">New Model reference.</param>
+        protected abstract void OnModelChanged(T oldValue, T newValue);
+        
+        /// <summary>
+        /// Raise the PropertyChanged event.
+        /// </summary>
+        /// <param name="propertyName">Name of the changed property.</param>
+        protected abstract void OnPropertyChanged(string propertyName);
+        
+    }
+}