lægge 2 tal sammen

jeg er helt ny til det her... hvad mangler jeg

Public Class Form1
    Dim Val1 As Integer
    Dim val2 As Integer
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click


        Val1 = (TextBox1.Text)

        Dim str As String = TextBox1.Text

        str.t()
        val2 = TextBox2.Text

        TextBox1.Text = (Val1 + val2)
    End Sub

    Private Sub TextBox3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox3.TextChanged

    End Sub
End Class