Caliburn Micro Guard方法未评估属性更改 [英] Caliburn Micro Guard Methods not evaluating on property change

问题描述

我一直在使用Caliburn Micro MVVM框架，并且在保护方法方面遇到一些问题.

I've been playing with the Caliburn Micro MVVM framework and am having some problems with guard methods.

我有一个视图模型:

public class MyViewModel : PropertyChangedBase, IMyViewModel

财产:

public DateTime? Date
{
   get{return this.date; }
   set
   {
      this.date = value;
      this.NotifyOfPropertyChange(() => Date);
   }
}

此外，我的视图模型中有一个带有防护方法的方法

Also, i have a method in my view model with a guard method

public void Calculate()
{
    // ..some code..
}

public bool CanCalculate()
{
    return this.Date.HasValue;
}

在我看来还有一个按钮:

And a button in my view:

我遇到的问题是，加载时会执行CanCalculate方法，但是当我在文本字段中输入值时，它不会重新评估CanCalculate方法.我在设置数据绑定视图模型属性时触发了属性更改事件，那么可能是什么问题?

The problem I am having is that the CanCalculate method executes when loading but when I enter values into the text fields, it doesn't reevaluate the CanCalculate method. I am firing the property changed event on setting the databound view model properties so what could be the problem?

推荐答案

好，我知道了.我没有意识到您必须解雇警卫方法通知，以为框架已经做到了，但这是有道理的.

Ok I figured it out. I didn't realise that you have to fire the guard method notification, thought the framework did that, but it makes sense.

所以我将属性设置器更改为:

So I change my property setter to:

public DateTime? Date
{
   get
   {
      return this.date; 
   }
   set
   {
      this.date = value;
      this.NotifyOfPropertyChange(() => Date);
      this.NotifyOfPropertyChange(() => CanCalculate);
   }
}

并将我的 CanCalculate 方法更改为属性:

and changed my CanCalculate method to a property:

public bool CanCalculate
{
    get
    {
        return this.Date.HasValue;
    }
}

现在一切正常:)

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