Processing parameters before calling the base constructor

问题

is it possible to process parameters before passing them into a base constructor?

As in:

A --> B

Where A is an abstract class and B is the child class.

A's constructor is like so:

Protected A (MyObject myObject)

B's constructor is like so:

Public B (string objectName)

I want it to be something like this

Public B (String objectName) : base (MyObject myObject)
{
myObject = new MyObject (objectName);
}

回答1:

If you want to do something non-trivial (that doesn't fit naturally into a single expression that you can inline into the base call), then the only way to do that is in a static method, for example:

public B (string objectName) : base (SomethingComplex(objectName))
{
    //...
}
static MyObject SomethingComplex(string objectName)
{
    // this can now be arbitrarily complex
    if(string.IsNullOrWhiteSpace(objectName))
        throw new ArgumentException("objectName")
    // etc
    return new MyObject(objectName);
}

回答2:

Yes, but only as a single expression:

public B(String objectName) : base(new MyObject(objectName)) {
}

Note that since this runs before the class is constructed, it cannot access instance members.

If you want to run more than a single expression (eg, parameter validation), you can call a static method.

来源：https://stackoverflow.com/questions/15027423/processing-parameters-before-calling-the-base-constructor