如何使用C＃明确方法调用顺序？

Question

How can I make method invocation order explicit with C#?

I want to make it explicit in code that one method should be called before the other, somewhat similar to the way callbacks work in JavaScript. I'm thinking that something like an array or List of Action might do the trick, but am not sure if this the best way, given what I am trying to achieve - it winds up being a better experience for the user if things happen in a certain order, but I want to make this explicit through code, instead of adding a comment.

Here's what I have so far:

Action<dynamic>[] deleteOperations = new Action<dynamic>[2];
deleteOperations[0] = (resource => this.RemoveImageFromDatabase(resource));
deleteOperations[1] = (filename => _blobStorage.DeleteBlob(filename));

Answer 1

That can be a difficult question, especially without more information. Why not provide a method that performs the desired actions in the order that you require?

void Delete(Resource resource, String filename) {
    try {
        this.RemoveImageFromDatabase(resource);
        }
    catch {
        }
    try {
        _blobStorage.DeleteBlob(filename);
        }
    catch {
        }
    }

This ensures that order is as required and gives you greater control over the operation (allowing you to log exceptions for example).

Answer 2

Have you looked into temporal coupling? Basically, you make the second function dependent on the first.

I don't know if this will help in your situation, but you end up with something like this:

var first = FirstMethod(p1, p2);
var second = SecondMethod(first, p3);

With the second call dependent on the first, you can't call them out of order.

There are some links and ideas in this thread:

How to deal with temporal coupling?