當我們用MVVM的時候要實現INotifyPropertyChanged,每次都要實現這個接口比較麻煩，所以基類的作用就體現出來了。代碼如下：
public class ViewModelBase : INotifyPropertyChanged, IDisposable
{
public event PropertyChangedEventHandler PropertyChanged;
public bool IsInDesignMode;
/// <summary> 顯示名稱 </summary>
public virtual string DisplayName { get; protected set; }
#region 構造
public ViewModelBase()
{
}
#endregion
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
private static string GetProperyName(string methodName)
{
if (methodName.StartsWith("get_") || methodName.StartsWith("set_") ||
methodName.StartsWith("put_"))
{
return methodName.Substring(4);
}
throw new Exception(methodName + " not a method of Property");
}
protected void SetProperty<T>(ref T name, T value)
{
if (object.Equals(name, value)) return;
name = value;
string propertyName = GetProperyName(new System.Diagnostics.StackTrace(true).GetFrame(1).GetMethod().Name);
this.OnPropertyChanged(propertyName);
}
#region IDisposable Members
public void Dispose()
{
this.OnDispose();
}
/// <summary>
/// 若支持IDisposable，請重寫此方法，當被調用Dispose時會執行此方法。
/// </summary>
protected virtual void OnDispose()
{
}
#endregion
}
public class CommandBase : System.Windows.Input.ICommand
{
private Action<Object> _doWork;
private readonly Func<object, bool> _canExecute;
/// <summary>
/// 實例化一個CommandBase對象
/// </summary>
/// <param name="doWork">委托一個有object類型參數的命令執行函數</param>
/// <param name="canExecute">委托一個有object類型參數的命令是否能被執行的函數（可選）</param>
/// <exception cref="ArgumentNullException">參數command不可以為null引用</exception>
public CommandBase(Action<object> doWork, Func<object, bool> canExecute = null)
{
if (doWork == null)
throw new ArgumentNullException("doWork");
_canExecute = canExecute;
_doWork = doWork;
}
public bool CanExecute(Object parameter)
{
return true;
}
public void Execute(Object parameter)
{
if (this._doWork != null)
this._doWork(parameter);
}
public event EventHandler CanExecuteChanged
{
add { }
remove { }
}
}
使用方式如下，例：
public class TestViewModel : ViewModelBase
{
public TestViewModel()
{
this.LoadCommand = new CommandBase((Object parameter) => Loading());
}
#region 屬性
private string _name;
/// <summary> 是否可用 </summary>
public string IsEnable
{
get { return _name; }
set
{
base.SetProperty<string>(ref this._name, value);
}
}
#endregion
#region 命令
/// <summary>
/// 窗口加載命令
/// </summary>
public ICommand LoadCommand { get; set; }
#endregion
#region 方法
/// <summary>
/// 初始化方法
/// </summary>
public void Loading()
{
}
#endregion
}
看了例子后，是不是感覺很簡單呢？詳細的測試代碼會再后續的文章中提供給大家參考。