C#

if(NewFrameDelegate!=null)
NewFrameDelegate();

class LocalSource {
 public event NewFrameDelegate NewFrame;
 
 // ...

 private void MoveToNewFrame(){
  Bitmap bitmap = SomeMethodToMakeFrameImage();
  NewFrameDelegate newFrame = NewFrame;
  if(newFrame != null) newFrame(bitmap);
 }
}

class ViewingWindow : UserControl { // or whatever
 void SomeMethod() {
  LocalSource source = new LocalSource(this);
  source.NewFrame += bitmap => {
   // whatever
  };
 }
}

interface INewFrameListener {
 void NewFrame(Bitmap bitmap);
}

class LocalSource {
 // ...

 private void MoveToNewFrame(){
  Bitmap bitmap = SomeMethodToMakeFrameImage();
  INewFrameListener newFrameListener = ViewingWindow as INewFrameListener;
  if(newFrameListener != null) newFrameListener.NewFrame(bitmap);
 }
}

class ViewingWindow : UserControl, INewFrameListener {
 void NewFrame(Bitmap bitmap) {
  // whatever
 }
}

var specificControl= ViewingWindow as YourType;
if(specificControl!=null && speciicControl.NewFrameDelegate!=null )
    speciicControl.NewFrameDelegate.

Pete O'Hanlon wrote:

Univote countered.

protected void UpdateData()
        {
            int intQuantity = 0;
            SqlConnection con = new SqlConnection("Your Connectionstring here");
            SqlCommand cmd = new SqlCommand("update product set quantity=@Quantity where productname=@Product", con); ;
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Quantity", intQuantity - 10);
            cmd.Parameters.AddWithValue("@Product", "Sugar");
            cmd.ExecuteNonQuery();
        }

nitin_ion wrote:

Also is caching good?

michae110 wrote:

You have to order them correctly,