C# - Example to Refactor-proof reference to members

最新推荐文章于 2025-02-05 14:42:52 发布

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本文介绍了如何通过Lambda表达式在INotifyPropertyChanged接口中实现refactor-proof引用，避免代码重构时可能引入的问题。通过实例演示了如何在ObservableConcreteObject类中使用Lambda表达式替代传统字符串参数，确保代码的健壮性和可维护性。

as we have discussed on the previous example that we have introduce the code snippet like this (see here):

serializationContext.AddProperty(x => x.BirthDate);

in this post, we are going to present a way that demonstrate how we can leverage the Lambda expression and effectively achieve refactor-proof references.

Our example is more about a very typical use case - the INotifyPropertyChanged impl. Where normally we will create a Invoke Pattern, and to that patter, one parameter is necessary, that is the name of the parameter.

normally , if we give a string for that name, we loose the ability to guard against changes when code is refactored. So, if we allow passing of a static typed LambdaExpression, such as this (this is a base class that will implements the IPropertyChanged)

  public class ObservableObject : INotifyPropertyChanged
  {
    public event PropertyChangedEventHandler PropertyChanged;

    #region Protected
    protected void InvokePropertyChanged()
    {
      throw new NotImplementedException();
    }
    protected void InovkePropertyChagned(string name)
    {
      throw new NotImplementedException();
    }
    protected void InvokePropertyChanged(Expression<Func<object>> property_)
    {
      System.Diagnostics.Debug.Assert(property_ != null);
      var body = property_.Body;
      var memberAccessExpression = ((MemberExpression)body);
      var memberName = memberAccessExpression.Member.Name;
      Console.WriteLine("InvokePropertyChanged on {0}", memberName);
    }

    #endregion Protectedk
  }

So when we define a Concrete Observable class, and when we need to notify the changes, such as this

public class ObservableConcreteObject : ObservableObject
  {
    private string m_message;

    public string Message
    {
      get { return m_message; }
      set
      {
        m_message = value;
        
        InvokePropertyChanged("Message");
      }
    }
  }

You can actually change the call to InvokePropertyChanged as this:

public string Message
    {
      get { return m_message; }
      set
      {
        m_message = value;
        // you can invoke like this;
        InvokePropertyChanged(() => this.Message);
      }
    }

So, all this is possbile when we try to pass in a lambda expression.