Problem with SessionState/ViewState

The answer to this is probably something I'll go d'oh! over once I see it but here's my problem:

I'm trying to use SessionState or ViewState to pass a variable back to the same page so that the same page can pull up different sets of data. This way I don't have to code 1500 different pages. Unfortunately the page has to be refreshed before the values will pass. Unfortunatly I have found several references to this on the net but no solutions. Passing the SessionState to another page works fine but I cannot pass the SessionState or the ViewState immediately back to the originating page. I could due this through the URL but I don't the data visible.
My code is somewhat simple because I wanted to see if this would work before I decided to use it:
dim searchString as string
dim typeString as string

If Not IsPostBack Then
'set sql query
OleDbDataAdapter1.SelectCommand.CommandText
= "SELECT tblBuildings.fldBuilding,
tblBuildings.fldBuildingKey,
tblContacts.fldContactKey,..."
'fill
OleDbDataAdapter1.Fill(PdDataSet1)
Page.DataBind()

Response.Write("Session ID = " &
Session.SessionID & " -- ")
Response.Write("Search String = " & ViewState
("searchString"))

Else
'load viewstate variables
searchString = ViewState("searchString")
typeString = ViewState("typeString")

'set new sql query
OleDbDataAdapter1.SelectCommand.CommandText
= "SELECT tblBuildings.fldBuilding,
tblBuildings.fldBuildingKey,
tblContacts.fldContactKey,
tblDepartments.fldPrimaryKey FROM
tblBuildings..."

'fill
OleDbDataAdapter1.Fill(PdDataSet1)
Page.DataBind()
Response.Write("Search String = " & ViewState
("searchString"))

End If
End Sub

Private Sub searchButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles searchButton.Click

typeString = searchText.Text
ViewState("typeString") = typeString
Session.Add(typeString, typeString)