C#

public delegate void ProgressChangeHandler(int progress);

interface CRInterface
{
  event ProgressChangeHandler ProgressChanged;
  int ProcessTWriting(ref byte[] WDat, ref int pb_value)
}

class MyCR: CRInterface
{
  public event ProgressChangeHandler ProgressChanged;
  
  public int ProcessTWriting(ref byte[] WDat, ref int pb_value)
  {
    status = AttemptWrites(ref pb_value);
  } 
  
  private int AttemptWrites(ref int pb_value)
  {
     for (int i = 0; i < ((wDat.Length) / 4); i++)
     {
        RaiseProgressChange(i);
        //as it does writes, I want to set pb_value here to % complete
     }
  }
  
   private void RaiseProgressChange(int progress)
   {
     if(ProgressChanged!= null)
     {
       ProgressChanged(progress);
     }
   }
}

// call this line just below where you create the instance of CR5 class
private FormLoad(...)
{
  cr.ProgressChanged += new ProgressChangeHandler(CR_ProgressChanged);
}

private void CR_ProgressChanged(int progress)
{
  progressBar.Value = progress;
}

public event ProgressChangeHandler ProgressChanged; 

public delegate void ProgressChangeHandler(int progress);

public event ProgressChangeHandler ProgressChanged;

public void GetPC(...)
{
   cr.ProgressChanged += new ProgressChangeHandler(updateProgressBar); //cr is instance of CR5 through iCR interface/factory
   cb.ProgressChanged += new ProgressChangeHandler(updateProgressBar); //cb is C_Comm 
}

public int updateProgressBar(int i)
{
    pb.Value = i;
}

public delegate void ProgressChangeHandler(int progress);
public interface iCR
{
    event ProgressChangeHandler ProgressChanged;
}

public event ProgressChangeHandler ProgressChanged;
private int AttemptWrites()
{
   for(i=0...)
   {
        RaiseProgressChange(i);
   }
}

private void RaiseProgressChange(int progress)
{
    if (ProgressChanged != null)
    {
         ProgressChanged(progress);
    }
}

public delegate void ProgressChangeHandler(int progress);

public class C_Comm{
    public event ProgressChangeHandler ProgressChanged;

    public int Read(byte[] data, int ind)
    {
        for(int i...)
        {
            RaiseProgressChange(i);
        }
    }

    private void RaiseProgressChange(int progress)
    {
        if (ProgressChanged != null)
        {
            ProgressChanged(progress);
        }
    }
}