两个类之间的数据绑定

Question

对象：在三个类之间使用DataBindings

环境：Visual Studio 2012、C#、WindowsForms

错误：DataBindings 在我的课程中不起作用

预期结果：

对象：

• 高度：数量
• 基数：数量
• 领域：制定
• AreaResult：结果

数据绑定：

Area.DataBindings.Add("H",Height,"Q");
Area.DataBindings.Add("B",Base,"Q");
AreaResult.DataBindings.Add("Display",Area,"Calculation");

Height.Q = 5;
Base.Q = 6;

应该产生 Area.Calculation 设置为 30 和 AreaResult.Display 也。

班级数量代码：

public class Quantity:INotifyPropertyChanged
{
   public Nullable<decimal> Q
   {
      get{ return this._q;}
      set
         {
            this._q = value;
            NotifyPropertyChanged("Q");
         }
   }

   public event PropertyChangedEventHandler PropertyChanged;

   protected void NotifyPropertyChanged(string name)
   {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }
}

类制定代码：

public class Formulate: INotifyPropertyChanged 
{ 
   public Nullable<decimal> H
    {
        get { return this._h; }
        set
        {
            this._h = value;
            NotifyPropertyChanged("H");
        }
    }
    private Nullable<decimal> _h;


    public Nullable<decimal> Q
    {
        get { return this._q; }
        set
        {
            this._q = value;
            NotifyPropertyChanged("Q");
        }
    }
    private Nullable<decimal> _h;


    public Nullable<decimal> Calculation
    {
        get { return this._calculation; }
        set
        {
            this._calculation = H/Q;
            NotifyPropertyChanged("Caltulation");
        }
    }
    private Nullable<decimal> _calculation;

    public event PropertyChangedEventHandler PropertyChanged;

    protected void NotifyPropertyChanged(string name)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }
}

类结果代码：

public class Result:INotifyPropertyChanged
{
   public Nullable<decimal> Display
   {
      get{ return this._display;}
      set
         {
            this._display = value;
            NotifyPropertyChanged("Display");
         }
   }

   public event PropertyChangedEventHandler PropertyChanged;

   protected void NotifyPropertyChanged(string name)
   {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }
}

Answer 1

这应该可以解决问题：

public class Formulate: INotifyPropertyChanged 
{ 
   public Nullable<decimal> H
    {
        get { return this._h; }
        set
        {
            this._h = value;
            NotifyPropertyChanged("H");
            NotifyPropertyChanged("Calculation");
        }
    }
    private Nullable<decimal> _h;


    public Nullable<decimal> Q
    {
        get { return this._q; }
        set
        {
            this._q = value;
            NotifyPropertyChanged("Q");
            NotifyPropertyChanged("Calculation");
        }
    }
    private Nullable<decimal> _h;


    public Nullable<decimal> Calculation
    {
        get { return _h == null || _q == null ? null : _h.Value / _q.Value; }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void NotifyPropertyChanged(string name)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }
}