Tambah Line di RichTextBox

richtextbox.Text = "Line1"  &  Environment.NewLine & "Line2" & Environment.NewLine & "Line3" & Environment.NewLine & "Line4"

cek isi dataGridView di VB.Net Express 2010

if (DataGridView1.RowCount = 0) then
     MessageBox.Show("DataGridView is empty") 
end if