Refreshing Datagridview From A Second Form?

I am trying to refresh a datagridview from a second form to display newly written data. I have read the posts on this topic and can't figure mine out. My first form opens and you input data into text fields, etc. and then you need to select items from one table to copy and write to a new table. The datgridview on the first form shows the new table, and I have a new form that pops up to select the line items to add. Everything works perfectly except when I close the selection form after selecting lines, I would like the datgridview on the first form to refresh to show that the lines have been selected and displayed in the datagrid.

My data is loaded into the datagridview as so;

Public
Sub ShowVoucherLines()
cmd =

[Code]......