WPF MVVM设计模式的ViewModelBase和CommandBase代码

ViewModelBase和CommandBase代码的整理如下：

 

1.ViewModelBase.cs

 

using System;
using System.ComponentModel;
using System.Linq.Expressions;
/// <summary>
/// WPF MVVC设计模式ViewMode基本功能类
/// </summary>
public abstract class ViewModelBase : INotifyPropertyChanged, IDisposable
{
    #region Public Properties
    /// <summary>
    /// 显示名称
    /// </summary>
    public virtual string DisplayName { get; protected set; }
    #endregion
    #region Constructor
    /// <summary>
    /// 实例化一个ViewModelBase对象
    /// </summary>
    protected ViewModelBase()
    {
    }
    #endregion
    #region INotifyPropertyChanged Members
    /// <summary>
    /// 触发属性发生变更事件
    /// </summary>
    /// <typeparam name="T">泛型标记，会匹配函数返回类型，不必手动填写</typeparam>
    /// <param name="action">以函数表达式方式传入属性名称，表达式如下即可：()=>YourViewModelProperty</param>
    protected void OnPropertyChanged<T>(Expression<Func<T>> action)
    {
        var propertyName = GetPropertyName(action);
        OnPropertyChanged(propertyName);
    }
    private static string GetPropertyName<T>(Expression<Func<T>> action)
    {
        var expression = (MemberExpression)action.Body;
        var propertyName = expression.Member.Name;
        return propertyName;
    }
    private void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            var e = new PropertyChangedEventArgs(propertyName);
            handler(this, e);
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
    #endregion
    #region IDisposable Members
    public void Dispose()
    {
        this.OnDispose();
    }
    /// <summary>
    /// 若支持IDisposable，请重写此方法，当被调用Dispose时会执行此方法。
    /// </summary>
    protected virtual void OnDispose()
    {
    }
    #endregion
}

 

 

2.CommandBase.cs

 

using System;
using System.Windows.Input;
/// <summary>
/// WPF MVVC设计模式命令基本功能类
/// </summary>
public class CommandBase : ICommand
{
    #region Private Fields
    private readonly Action<object> _command;
    private readonly Func<object, bool> _canExecute;
    #endregion
    #region Constructor
    /// <summary>
    /// 实例化一个CommandBase对象
    /// </summary>
    /// <param name="command">委托一个有object类型参数的命令执行函数</param>
    /// <param name="canExecute">委托一个有object类型参数的命令是否能被执行的函数（可选）</param>
    /// <exception cref="ArgumentNullException">参数command不可以为null引用</exception>
    public CommandBase(Action<object> command, Func<object, bool> canExecute = null)
    {
        if (command == null)
            throw new ArgumentNullException("command");
        _canExecute = canExecute;
        _command = command;
    }
    #endregion
    #region ICommand Members
    public void Execute(object parameter)
    {
        _command(parameter);
    }
    public bool CanExecute(object parameter)
    {
        if (_canExecute == null)
            return true;
        return _canExecute(parameter);
    }
    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }
    #endregion
}

 

关于WPF MVVM设计模式文档（Josh Smith），请阅读：http://msdn.microsoft.com/zh-cn/magazine/dd419663.aspx

此代码是Josh Smith的范例修改版本。