Variable not declared! help w/ VB

1

so here is what it looks like:

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim subjectnumber As Integer = 0
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If
            TextBox1.Text = "Subject One"
            subjectnumber += 0
        Else : subjectnumber += 1
        End If
    End Sub

    Private Sub TextBox28_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox28.TextChanged
        TextBox28.Text = subjectnumber
    End Sub
End Class

i got an error on subjectnumber when using it, what am i doing wrong?