Use the below code:
In Design Page:
<div id="DivCSRF" runat="server"></div>
In Code Page:
Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
DivCSRF.InnerHtml = AntiForgery.GetHtml().ToString()
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
DivCSRF.InnerHtml = AntiForgery.GetHtml().ToString()
If IsPostBack Then
Try
AntiForgery.Validate()
Catch ex As Exception
Response.Redirect("~/Unauthorize.aspx", False)
Exit Sub
End Try
End If