Is there a way to intercept setters and getters in C#?

Question

In both Ruby and PHP (and I guess other languages as well) there are some utility methods that are called whenever a property is set. ( *instance_variable_set*

Answer 1

It is possible to do directly in the property body itself, but then you need to use a proper backing field instead of auto-implemented properties.

private string firstName;

public string FirstName 
{ 
  get { return firstName;} 
  set 
  {
    if(check(value))
    {
       firstName = value;
    }
  } 
}

Even with auto-implemented properties you get a backing field - this is generated by the compiler and you don't have direct access to it.

---

Edit:

Seeing as you don't want a backing field, you have other options - using an AOP tool such as PostSharp could help with that.

Answer 2

Yes, of course...

In your example you are using automatic properties, without a backing field.... You just need to create a backing field for your property, and then you can do what you want in the setter and getter.

example:

private string firstName;

public string FirstName
{
 get { return firstName; }

 set { doMethod(); firstName = value;}
}

Answer 3

I know this has been properly answered but I'll include an example to show you the syntax to achieve what you want:

public class Person
{
    private 
    public string FirstName
    {
        get
        {
            return _firstName;
        }
        set
        {
            // see how we can call a method below? or any code for that matter..
            _firstName = SanitizeName(value);
        }
    }
}

Answer 4

You will have to write the properties in full to achieve this.

Answer 5

As far as I know, you have to use a backing field and put the call to the other method inside the setter thusly:

public class Person {
    private string firstName;
    private string lastName;

    public string FirstName {
        set { 
            DoSomeStuff();
            firstName = value;
        }
        get { return firstName; }
    }

    public string LastName { 
        set {
            DoSomeStuff();
            lastName = value;
        }
        get { return lastName; }
    }
}

Answer 6

You cant use automatic properties. You would have to dinfe the property out the old fashion way with a backing field and call the method manually.

public class Person
{
    private string _FirstName;
    public string FirstName 
    { 
        get
        {
            return _FirstName;
        }
        set
        {
            SomeMethod();
            _FirstName = value;
        }
    }
    private void SomeMethod()
    {
        //do something
    }

}