Overriding classes in c# and accessing a virtual method which uses an override method

Question

I am working with overriding methods in C# for the first time and I think I have a good grasp of the basics. However my methods are a little more complex and some call methods within the methods.

I am essentially trying to save myself code writing by finding a way to use the base class method but call the overriden method that the base class method uses.

Here is an example of my problem, as I might not be explaining it too well:

namespace exampleCode
{
    public class BaseClass : AnotherClass
    {
        public static string OrderStorageContainer = "Deliverables";

        public virtual string CustomerStorageContainer = "CustomerDocs";

        public virtual string GetSomething(typeStorage st, string FileName)
        {
            if (String.IsNullOrWhiteSpace(FileName))
            {
                throw new ArgumentNullException("FileName", "The filename of the file should be supplied!");
            }

            var c = GetReference(GetName(st));        
            return c.ToString();
        }
        public virtual string GetName(typeStorage st)
        {
            switch (st)
            {
                case typeStorage.CustomerProvided:
                    return CustomerStorageContainer.ToLower();
                case typeStorage.SystemGenerated:
                    return OrderStorageContainer.ToLower();
            }
            throw new InvalidOperationException("No container defined for storage type: " + st.ToString());
        }

        public virtual string GetReference()
        {
            //does stuff
        }
    }

    public class DervivedClass : BaseClass
    {
        public static string QuoteStorageContainer = "QuoteDeliverables";

        public override string CustomerStorageContainer = "QuoteCustomerDocs";

        public override string GetSomething(typeStorage st, string FileName)
        {
            if (String.IsNullOrWhiteSpace(FileName))
            {
                throw new ArgumentNullException("FileName", "The filename of the file should be supplied!");
            }

            var c = GetReference(GetName(st));        
            return c.ToString();
        }

        public override string GetName(typeStorage st)
        {
            switch (st)
            {
                case typeStorage.CustomerProvided:
                    return CustomerStorageContainer.ToLower();
                case typeStorage.SystemGenerated:
                    return QuoteStorageContainer.ToLower();
            }
            throw new InvalidOperationException("No container defined for storage type: " + st.ToString());
        }

    }
}

Basically, I want the Derived class to use the override GetSomething method. However, I want it to call the Base Class GetReference() method with the result from the overriden GetName() method.

Is this along the right lines? I've been finding it difficult to find a similar exmaple online.

Any pointers would be great!

Solution 1

Your implementation seems correct. It will be correct until you don't override GetReference() method in your DerivedClass.

If you want var c = GetReference(GetName(st)); this line to always call base class, you should take precaution by writing it as base.GetReference(GetName(st))

Solution 2

I think you're on the right track. You'd better use base and this to avoid confusion and force compiler use the implementation you want.

Comments

[Alexander Derck]

Looks right to me, as long as you don't override the GetReference method you'll call the base one. If you would override it, you can still use base.GetReference().