using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var model=new OnlineModel();

        model.id="ABC";

        model.onlineId="123";

        var onlineC=new Online();

        onlineC.BaseModel=model;

        onlineC.writeOnline();

        onlineC.writeColumn("ABC");

    }

}

​

public class C

{

    public baseModel BaseModel{get;set;}

    public void write()

    {

        Console.WriteLine(this.BaseModel.id);

​

    }

    public virtual void writeColumn(string a)

    {

        Console.WriteLine(a);   

    }

    public void writeBatch(){

    if (this.BaseModel is BatchModel)

        {

            this.write();

            var model=this.BaseModel as BatchModel; 

            Console.WriteLine(model.batchId);   

        }   

    }

}

//public class batch :C

//{

​

//  public void writeBatch(){

//  if (this.BaseModel is BatchModel)

//      {

//          this.write();

//          var model=this.BaseModel as BatchModel; 

//          Console.WriteLine(model.batchId);   

//      }   

//  }

//}

​

public class Online:C

{

    public void writeOnline(){

    if (this.BaseModel is OnlineModel)

        {

            this.write();

            var model=this.BaseModel as OnlineModel;    

            Console.WriteLine(model.onlineId);  

        }   

    }

    public override void writeColumn(string a)

    {

        Console.WriteLine("Online" + a);    

    }

}

​

public class baseModel

{

    public string id {get;set;}

}

​

public class OnlineModel:baseModel

{

    public string onlineId{get;set;}     

}

​

public class BatchModel:baseModel

{

    public string batchId{get;set;}

}