simple error?

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim rbg1, rbg2, rbg3 As Integer
        If TextBox1.Text = "" Then
            TextBox1.Text = "0"
        ElseIf TextBox1.Text > "255" Then
            TextBox1.Text = "255"
        Else
            rbg1 = TextBox1.Text
        End If

        If TextBox2.Text = "" Then
            TextBox2.Text = "0"
        ElseIf TextBox2.Text > "255" Then
            TextBox2.Text = "255"
        Else
            rbg2 = TextBox2.Text
        End If

        If TextBox3.Text = "" Then
            TextBox3.Text = "0"
        ElseIf TextBox3.Text > "255" Then
            TextBox3.Text = "255"
        Else
            rbg3 = TextBox3.Text
        End If

        Me.BackColor = Color.FromArgb(rbg1, rbg2, rbg3)

    End Sub
End Class