我有两个属性,其中第一个属性(FXRate)更改时,必须更新后一个属性(CalulcatedValue).

我可以通过将CalulcatedValue设置为ReadOnly并从FXRate设置器中调用OnPropertyChanged(“ CalculatedValue”)来实现此目的.

public double FXRate {
    get { return _fXRate; }
    set {
        Set(_fXRate, value, "FXRate");
        OnPropertyChanged("CaluclatedValue");
    }
}

public float CalculatedValue  
{
    get { return FXRate * SomeOtherValue;}
}

但是我知道CalulcatedValue属性会被调用很多(用于多个LINQ查询等).我当时考虑的是,吸气剂应该非常快地返回该值,并正计划为其提供支持.

public double FXRate 
{
    get { return _fXRate;}
    set {
        Set(_fXRate, value, "FXRate");
        CalculatedValue = 0; //how to set CalculatedValue since it's setter is calculating it with its logic, i.e. the value parameter is not needed ?
    }
}
private double _fXRate;

public float CalculatedValue  
{
    get { return _calculatedValue; }
    set {
        __calculatedValue = FXRate * SomeOtherValue); //consider this line takes some effort to be calculated -> instead of SomeOtherValue there might be pretty complex logic here to get the result
        OnPropertyChanged("CalculatedValue");
    }
}
private float _calculatedValue;

现在应如何设置CalulcatedValue？它不需要传递任何值参数,因为逻辑位于设置器内.线

CalulcatedValue=0

就是现在发生的愚蠢事情.

解决方法:

如果需要INotifyPropertyChanged通知,则将其添加到FXRate属性(和/或可能更改CalculatedValue值的任何属性)中,然后在其中进行计算：

private double _fXRate;
private float _calculatedValue;

public double FXRate 
{
  get { return _fXRate;}
  set {
      Set(_fXRate, value, "FXRate");
      _calculatedValue = _fxRate * SomeOtherValue;
      // this will update any control depending on the `CalculatedValue` notification
      OnPropertyChanged("CalculatedValue");
  }
}

public float CalculatedValue  
{
  get { _calculatedValue; }
}

或者,如果您希望将计算推迟到第一次读取(因为您将多次更新FxRate或实际读取CalculatedValue之前的某些操作),则可以执行以下操作：

private double _fXRate;
private float _calculatedValue;
private bool _calculatedValueIsDirty = true;

public double FXRate 
{
  get { return _fXRate;}
  set {
      Set(_fXRate, value, "FXRate");
      _calculatedValueIsDirty = true;
      OnPropertyChanged("CalculatedValue");
  }
}

public float CalculatedValue  
{
  get { 
      if(_calculatedValueIsDirty) {
        _calculatedValue = _fxRate * SomeOtherValue;
        _calculatedValueIsDirty = false;
      }
      return _calculatedValue;
  }
}

除非预先计算的值再次变脏(通过更改FXRate),否则随后对CalculatedValue的读取将很快返回.

PS：如果有类似多线程的内容,请在必要时应用锁:-)