CODEWITHSUNDEEP
c#expression-trees
Gluip
Gluip

Reputation: 2987

Parameterizing propertynames using expressions

I am having a piece of code in which i delegate certain properties of a class to another class if the class exists. Below you see the start time being defined on the TimeProvider if it exists. 

public override DateTime StartTime
{
   get
   {
       return (TimeProvider != null) ? TimeProvider.StartTime : base.StartTime;
   }
   set
   {
       if (TimeProvider != null)
       {
           TimeProvider.StartTime = value;
       }
       else
       {
           base.StartTime = value;
       }
    }
 }

Now my 'problem' is that i have a lot more properties (like endtime,currentime) i delegate to the TimeProvider if it is not null. So i would like to have code like:

public override DateTime StartTime
{
   get
   {
       return GetTime(()=>StartTime);
   }
   set
   {
       SetTime(()=>StartTime)
    }
 }

Where the ()=>StartTime expression is sometimes 'evaluated' on the TimeProvider and sometimes on the class itself (they share a baseclass). Can something like this be done? Preferably without using reflection.

Upvotes: 2

Views: 93

Answers (1)

Sleeper Smith
Sleeper Smith

Reputation: 3242

Cake

public class Foo
{
    private string _string1;
    public Foo foo { get; set; }

    private T GetProperty<T>(Func<Foo,T> getter)
    {
        return foo == null
                   ? getter(this)
                   : getter(foo);
    }

    private void SetProperty(Action<Foo> setter)
    {
        if (foo == null)
            setter(this);
        else
            setter(foo);
    }

    public string String1
    {
        get { return GetProperty(a => a._string1); }
        set { SetProperty(a => a._string1 = value); }
    }
}

Upvotes: 1

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