remember selection from previous form

Just pass the id for the new member in the constructor of the edit form, and use it to select the right person in the datagrid.

Hope this helps.

In reply to your comment.
Say your second form was called EditForm, then you would create a constructor in this form that takes an int representing the selected members id. Then the form would use this information to select the right member, something like this (pseudocode):-

public class EditForm
    {
        public EditForm(int memberID)
        {
            datagrid1.SelectedPerson = from person in datagrid1.datasource where person.id == memberID;
        }
    }

Then you would open this form when the button is clicked like this:-

private void btnSaveAndEdit_Click(object sender, EventArgs e)
       {
           EditForm e = new EditForm(paulsID);
           e.showdialogue();
       }

This is obviously not real code, but should give you the idea of how to go about it.