ASP NET Stop other sub proc from executing after error - asp.net

Question

I am having a problem with my try catch block runs in the error:
database is not available
My problem is the try catch runs and catches the error, but it will not redirect to my error page. The code continues to execute the other subs. I have tried adding: exit, return, response.end. None of them worked. Thank you for your help.
Imports System.Data
Imports EUC
Imports System.Threading
Imports System.Data.SqlClient
Partial Class mpMain
Inherits System.Web.UI.MasterPage
Dim strSQL As String
Dim objData As clsDataAccess = New clsDataAccess()
Dim ds As New D
ataSet
Dim t1 As DataTable
Dim intSecurityLevel As String = 0
Dim strUser As String = UCase(Right(HttpContext.Current.User.Identity.Name.ToString(), 4))
Protected Sub ExpandNode(ByVal NodeName As String, ByVal PageName As String)
'More Code
End Sub
Protected Sub ExpandNode2(ByVal NodeNameMain As String, ByVal NodeName As String, ByVal PageName As String)
'More Code
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not (IsPostBack) Then
Try
strSQL = "Select SecurityLevel from tblSecurity where SFID = #SFID order by SecurityLevel"
Dim MyParameters1 As SqlParameter() = { _
New SqlParameter("#SFID", SqlDbType.VarChar) _
}
MyParameters1(0).Value = UCase(Right(HttpContext.Current.User.Identity.Name.ToString(), 4))
ds = objData.SQLExecuteDataset(strSQL, CommandType.Text, MyParameters1)
t1 = ds.Tables(0)
Catch ex As Exception
Dim sendError As New clsExceptionMessage
sendError.sendMessage(ex.Message, Request.Path, strSQL)
Response.Redirect("ErrorMessage.aspx", False)
End Try
End If
End Sub
Protected Sub TreeView1_TreeNodeDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles TreeView1.TreeNodeDataBound
'More Code
End Sub
Protected Sub TreeView1_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles TreeView1.DataBound
'More Code
End Sub
End Class

Answer 1

Firstly I would catch SQLException, you rarely want to catch a general exception.
In the catch block, set a boolean parameter such as
hasError = True
and once outside the try..catch block check for this to be true and redirect from there.