In C# Windows applications, below is a code example for action when pressing the OK button in the MessageBox alert box.

    var result = MessageBox.Show(@"Are You Sure?", @"Warning", 
                        MessageBoxButtons.OKCancel, 
                        MessageBoxIcon.Information);
             
  if (result.Equals(DialogResult.OK))
  {                   
        //Do Something
  } 

In our example, we first set the properties of our "MessageBox". Then we prepared our "if" block about what to do if the "OK" button is pressed.