how to get the current selected value from grid

Hi Good night. 

I need to do the following.

When selecting one or clicking on a row of the grid, obtain the value of the selected Id (current).

• The grid has a “SelectedRow” event?
• in test mode. I created a Button (AddSelected). When i select a row and then i push de button, I need to get the value (Id) of the current row. (now i am obtain only the value of the first row (Id = 86)

i put the code of the Add Selected button.

    public PXAction<CEEstimate> AddSelected;
    [PXButton(CommitChanges=true)]
    [PXUIField(DisplayName = "Add Selected")]
    protected virtual void addSelected()
    {
      CEEstimate row = viewCEEstimate.Current;
      CEEstimateEstimate rowd = viewCEEstimateEstimates.Current;
      //row.Description = CEEstimateEstimate.Current.Id.ToString();
      row.Description = rowd.Id.ToString();
    }

CEEstimate (viewCEEstimate) is the header and CEEstimateEstimate and viewCEEstimateEstimates is the detail

cna you helpme please