Which design pattern to use for flexible Message Sending?

c#, design-patterns

Solution

I am thinking of below solution:
Interface IMessageSystem
{
void Send();
}
Public class Email : IMessageSystem
{
   public void Send()
  {
    console.writeline("Message From Email");
  }
}
Public class SMS : IMessageSystem
{
   public void Send()
  {
    console.writeline("Message From SMS");
  }
}
Public class Twitter : IMessageSystem
{
   public void Send()
  {
    console.writeline("Message From Twitter");
  }
}
Interface ISendMessageStrategy
{
  void SendMessages();
}
Public class SendMessageStrategyForRoleA : ISendMessageStrategy
{
   Public void SendMessages()
  {
    Email objemail = new Email();
   objemail.Send();
   SMS objSMS = new SMS();
   objSMS .Send();
   Twitter objtwitter = new Twitter();
   objtwitter.Send();   
  }
}
Public class SendMessageStrategyForRoleB : ISendMessageStrategy
{
   Public void SendMessages()
  {
   SMS objSMS = new SMS();
   objSMS .Send();
  }
}
Public class SendMessageStrategyForRoleC  : ISendMessageStrategy
{
  Public void SendMessages()
  {  
    Twitter objtwitter = new Twitter();
    objtwitter.Send();
  }
}
Public class SendMessageSystem
{    
   public ISendMessageStrategy sendMessageStrategy;
   List<Keyvaluepair<string,ISendMessageStrategy>> lstkeyval = new List<Keyvaluepair<string,ISendMessageStrategy();
   public SendMessageSystem(string role)
   {
       lstkeyval.add(new keyvaluepair<string,ISendMessageStrategy>("A",new SendMessageStrategyForRoleA()));
       lstkeyval.add(new keyvaluepair<string,ISendMessageStrategy>("B",new SendMessageStrategyForRoleB()));
       lstkeyval.add(new keyvaluepair<string,ISendMessageStrategy>("C",new SendMessageStrategyForRoleC()));
       sendMessageStrategy = lstkeyval.where(x=>x.Key == role).Value;
   }
   public void SendMessage ()
   {
       sendMessageStrategy.SendMessages();
   }
}
public class programme
{
   static void main (string[] args)
   {
     SendMessageSystem objMessage = new SendMessageSystem("A");
     objMessage.SendMessage();
   }
}

Problem

I need to implement a Message Sending functionality based on Roles. - Role A: Message should be sent by Email and sms - Role B: Message should be sent by only Email - Role C: Message should be sent by only sms - Role D: Message should be sent by Twitter I have to accommodate for change regarding what Roles can use what Message Sending functionality, e.g. I need to be able to change Role B to also include sms. Any of the Roles may need any of the Message Sending functionality. I have considered having one Interface IMessageChannel with a method SendMessage. Then three classes implementing that interface, e.g. Email, SMS and Twitter. I am thinking of using the Strategy pattern and Factory? Is this correct? What Design Patterns should I consider to implement this?

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