ViewState Question

[wey97]

Dim str As String
 
    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
 
        If Page.IsPostBack Then
            str = ViewState("str")
        Else
            str = "Init"
        End If
 
        Response.Write(str)
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        str = TextBox1.Text
        ViewState("str") = str
    End Sub

When the page first loads, obviously "Init" prints. Then, I type in TextBox1 and click Button1. You would think that on the first PostBack, str would be printed but it isn't. It's not until the next Button1 click. So my question is, does the Page PostBack fire before the Button Click event fires? Seems to be backwards if that's the case...