CODEWITHSUNDEEP
c#design-patternsgenericsdelegates
Puzzled
Puzzled

Reputation: 3

Avoiding repetitive code in multiple similar methods (C#)

Greetings everyone!

I have a set of a few (and potentially will have dozens more) of very similar methods in C#. They all built on almost identical pattern:

ResultObjectType MethodX(...input parameters of various types...)
{
  nesting preparation code here...
  {
    {
      resultObject = ExternalClass.GetResultForMethodX(input parameters of MethodX);
    }
  }
  nesting result processing code here ...
  return resultObject;
}

Repeating/identical parts: ResultObjectType, preparation code, result processing code.

Different parts: ExternalClass method to call, input parameter set (number of input parameters, their types).

Important: I am not in control of the method signatures – cannot change them.

I am trying to avoid repeating all blocks of similar code with something like this:

ResultObjectType MethodX(...input parameters of various types...)
{
    return  UniversalMethod( 
                   new ExternalMethodDelegate(ExternalClass.GetResultForMethodX),
                   input parameters of MethodX...);
}

ResultObjectType UniversalMethod (Delegate d, input parameters of various types...)
{
    nesting preparation code...
    {
        {
           resultObject = 
              (d as ExternalMethodDelegate)(same input parameters as above);
        }
    }
    nesting result processing code...
    return resultObject;
}

So far I only managed to make it work in this manner in case where all parameters have the same known type at the time of coding. After a number of attempts to tackle this problem with generic delegates I am starting to think this is not possible to achieve. Even when my code compiles, it does not work at runtime. Any takers? Thanks in advance for your help!

Upvotes: 0

Views: 1875

Answers (2)

pabdulin
pabdulin

Reputation: 35219

Repeating/identical parts: ResultObjectType, preparation code, result processing code.

You should concentrate to make this parts as isolated as possible.

Another approach is code generation.

Upvotes: 0

porges
porges

Reputation: 30580

Here's an example using generic delegates:

int MethodY(int something, int other)
{
    return UniversalMethod(() => GetResultForMethodY(something, other));
}

string MethodX(string something)
{
    return UniversalMethod(() => GetResultForMethodX(something));
}

T UniversalMethod<T>(Func<T> fetcher)
{
    T resultObject;
    //nesting preparation code here...
    {
        resultObject = fetcher();
    }
    //nesting result processing code here ...
    return resultObject;
}

If ResultObjectType is always the same then you can remove all Ts.

Upvotes: 2

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