c＃基本功能串联，避免使用switch

Question

I am looking for a smarter way to call functions without using switch. My problem is as below: I have many function calls that read something like this.map.functionApple(); this.map.functionPeach(); this.map.functionOrange();

I am currently calling a parent function fruit("Orange") which basically is a huge function with switch which selects the function this.map.functionOrange() Is there a way where I can simply do:

this.map.function+name+();

Answer 1

There are a few basic ways to handle branching. You have the if ... else construct, which allows you to create two or more branches (else if). Then there is a switch, which simplifies the if ... else logic.

Another way is to look up the answer. This can be in a config file, a database or hashed in some way. Jon Skeet recommends a Dictionary with an action, which is one way of handling this via a hash construct.

Corey's suggestion of Command or Strategy do not solve the branching logic, per se, but give you a structured way of handling it. Using the Strategy pattern, for example, you can easily add new strategies to handle other fruit. Command also does not completely solve the branching "issue", but can be set up to solve the issue of having multiple types of fruit with different actions.

Answer 2

If i understood correctly you are looking for something like below:

using System.Reflection;
string name = "Orange";//Put your function name here....

//In your calling function:
MethodInfo yourMethod = this.map.GetType().GetMethod("function" + name);
object magicValue = magicMethod.Invoke(this,null);

Answer 3

Building on Jon's comment, using a Dictionary<string, action> is a simple and elegant approach. It would look something like this:

class StackOverflowExample
{
    private MapThing _map;
    private IDictionary<string, Action> _mapActions;

    public StackOverflowExample()
    {
        _map = new MapThing();

        _mapActions = new Dictionary<string, Action>
        {
            { "orange", _map.functionOrange },
            { "peach", _map.functionPeach },
            ...
        }
    }

    public void Fruit(string name)
    {
        // Now, instead of the giant switch statement...
        if (_mapActions.ContainsKey(name))
            _mapActions[name].Invoke();

        // Throw an exception if name not in dictionary
    }
}

Simple usage:

var example = new StackOverflowExample();
example.Fruit("orange");