Con este código para Visual Basic 2010 puedes ir añadiendo todas las filas que quieras a una datagridview insertando datos y pulsando guardar, hasta que decidas terminar pulsando cerrar. Cada vez que insertas datos, los textBox se limpian de los datos anteriores.
Public Class Form1
Dim row(4) As String
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Button1.Text = "Guardar"
Button2.Text = "Cerrar"
DataGridView1.ColumnCount = 4
DataGridView1.Columns(0).Name = "Fabricante"
DataGridView1.Columns(1).Name = "Modelo"
DataGridView1.Columns(2).Name = "Nombre recambio"
DataGridView1.Columns(3).Name = "Referencia"
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
row(0) = TextBox1.Text
row(1) = TextBox2.Text
row(2) = TextBox3.Text
row(3) = TextBox4.Text
Dim rowToSave As String() = New String() {row(1), row(2), row(3), row(4)}
DataGridView1.Rows.Add(row)
TextBox1.Text = ""
TextBox2.Text = ""
TextBox3.Text = ""
TextBox4.Text = ""
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Me.Close()
End
End Sub
End Class
Saludos