CODEWITHSUNDEEP
c#
Nugs
Nugs

Reputation: 5783

Accessing properties of a generic types

Good morning,

I have 2 objects that i need to work with from a third party. These objects are almost identical (at least the part i need to access are. Currently i have separate methods to handle each object and i would like to see, with the help of you kind folk, if i can convert this into a generics that can handle both objects.

public static ObjectOut Method1(Object1 obj1)
{
   if (obj1.ErrorCode == 0)
   {
      //do something
   }
}

public static ObjectOut Method2(Object1 obj2)
{
   if (obj2.ErrorCode == 0)
   {
      //do something
   }
}

If i convert this into a single generic method, how would i access the "ErrorCode" property of the object? Any help or guidance would be greatly appreciated.

Thanks

Upvotes: 1

Views: 177

Answers (4)

Heinzi
Heinzi

Reputation: 172200

If both types of object have a common supertype, you don't even need generics:

public static ObjectOut Method(ICommonInterfaceWithErrorCodeProperty obj)
{
    if (obj.ErrorCode == 0)
    {
        //do something
    }
}

If the properties just happen to have the same name, you can refactor your code such that "common code" is in a separate method. I'll give you two examples:

  1. DoSomething is a big common block.
  2. DoSomething needs to access properties of your objects.

In the first case, you can just extract DoSomething:

public static ObjectOut Method1(Object1 obj1)
{
   if (obj1.ErrorCode == 0)
   {
      return DoSomething();
   }
}

public static ObjectOut Method2(Object1 obj2)
{
   if (obj2.ErrorCode == 0)
   {
      return DoSomething();
   }
}

public static ObjectOut DoSomething() { ... }

In the second case, you extract all the values you need and pass them to your common method:

public static ObjectOut Method1(Object1 obj1)
{
     return Method(obj1.ErrorCode);
}

public static ObjectOut Method2(Object2 obj1)
{
     return Method(obj2.ErrorCode);
}

public static ObjectOut Method(int errorCode)
{
     if (errorCode == 0)
     {
         ...
     }
}

If you need to execute methods on your objects, you can pass lambdas to Method.

(And, obviously, you need to fix the fact that your methods don't return anything if the error code is non-zero. But I guess the compiler already told you that.)

Upvotes: 2

DarkSquirrel42
DarkSquirrel42

Reputation: 10257

i assume the 2 classes don't have a common base class / interface that holds all needed members...

what you can do is write a wrapper around those 2 objects that exposes all needed members and internally hands everything down to the object you are currently handling

something like

public class wrapper {
   private ClassA objA;
   private ClassB objB;
   public wrapper(ClassA obj)
   {
      objA=obj;
   }

   public wrapper(ClassB obj)
   {
      objB=obj;
   }

   public int? Property1 
   { 
      get 
      { 
         return objA?.Property1 ?? objB?.Property1; 
      } 
   } 
}

Upvotes: 0

Rahul
Rahul

Reputation: 77846

If they have any similar parent ... like an interface or abstract base class? then you can use where constraint saying 

public static ObjectOut Method1<T>(T obj1) where T : IBaseObject
{
   if (obj1.ErrorCode == 0)
   {
      //do something
   }
}

If not, then you will have to cast it and access accordingly like

public static ObjectOut Method1<T>(T obj1)
{
   if(obj1 is Object1)
  {
   if (((Object1)obj1).ErrorCode == 0)
   {
      //do something
   }
  }
}

Upvotes: 0

Tipx
Tipx

Reputation: 7505

To do what you want, you need them to have a parent (class or interface) with the ErrorCode defined. If you do, you could do a generic helper class such as :

public static class MyHelperClass<T> where T : TheCommonParent
{
    public static ObjectOut Method(T obj)
    {
       if (obj.ErrorCode == 0)
       {
          //do something
       }
    }
}

If you want your ObjectOut to be different, you might need to have a 2nd generic type in the class definition, but there is not enough information based on your question to know for sure.

Upvotes: 0

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