Execute Method Before and After Code Block

Question

How could I wrap some code in brackets to do the following?

MyCustomStatement(args){
// code goes here
}

So that before the code in the brackets executes, it'll call a method and when the code in the brackets finishes executing it will call another method. Is there such a thing? I know it seems redundant to do this when I can simply call the methods before and after the code and all, but I simply was curious. I don't know how to word this exactly because I'm new to programming.

Thanks!

I have no idea what you're asking. What do you mean by "wrap some code in brackets"? — James, Oct 21 '14 at 10:15
You mean you want to create an event? see [Events (C#)](http://msdn.microsoft.com/en-us/library/awbftdfh.aspx) — SmartDev, Oct 21 '14 at 10:17
Apply [Template method pattern](http://en.wikipedia.org/wiki/Template_method_pattern) — Sriram Sakthivel, Oct 21 '14 at 10:19

score 7 · Accepted Answer · answered Oct 21 '14 at 10:22

You can do this by storing the code in an abstract class that executes the "before" and "after" code for you when you call Run():

public abstract class Job
{
    protected virtual void Before()
    {
        // Executed before Run()
    }

    // Implement to execute code
    protected abstract void OnRun();

    public void Run()
    {
        Before();
        OnRun();
        After();
    }

    protected virtual void After()
    {
        // Executed after Run()
    }
}

public class CustomJob : Job
{
    protected override void OnRun()
    {
        // Your code
    }
}

And in the calling code:

new CustomJob().Run();

Of course then for every piece of custom code you'll have to create a new class, which may be less than desirable.

An easier way would be to use an Action:

public class BeforeAndAfterRunner
{
    protected virtual void Before()
    {
        // Executed before Run()
    }

    public void Run(Action actionToRun)
    {
        Before();
        actionToRun();
        After();
    }

    protected virtual void After()
    {
        // Executed after Run()
    }
}

Which you can call like this:

public void OneOfYourMethods()
{
    // your code
}

public void RunYourMethod()
{
    new BeforeAndAfterRunner().Run(OneOfYourMethods);
}

Good answer. How can I call OneOfYourMethods method with parameters and how can I receive return value of the method. — suphero, Apr 14 '15 at 12:07
@suphero see http://stackoverflow.com/questions/14738533/dispatch-invoke-new-action-with-a-parameter, http://stackoverflow.com/questions/4965508/how-can-i-pass-a-parameter-in-action — CodeCaster, Apr 14 '15 at 12:37

score 3 · Answer 2 · answered Oct 21 '14 at 10:24

To literally achieve what you want, you can use a delegate:

Action<Action> callWithWrap = f => {
    Console.WriteLine("Before stuff");
    f();
    Console.WriteLine("After stuff");
};

callWithWrap(() => {
    Console.WriteLine("This is stuff");
});

This requires adding "weird syntax" to your blocks and an understanding of how delegates and anonymous functions in C# work. More commonly, if you're doing this within a class, use the technique demonstrated in @CodeCaster's answer.

Execute Method Before and After Code Block

2 Answers2

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