>I think it's always better to be explicit. In your case you will reply on implicit cast.

Here is the method:

        ' Return a numeric value
        ' If it is corrupted, we redirect to the main page
        ' expC1 HTLM form variable
        Public Function GetProcessNumeric(ByVal tcField As String) As Integer
            Dim lcPrimaryKey As String = ""
            Dim lnPrimaryKey As Integer = 0
            Dim lnPrimaryKeyTemp As Double = 0

            ' If the key exists
            If oProcess.IsProcess(tcField) Then
                
                ' Get the value
                lcPrimaryKey = oProcess.GetProcess(tcField)

                ' If we have a value
                If lcPrimaryKey.Length > 0 Then

                    ' If we have digit only
                    If oProcess.oApp.IsFilter09(lcPrimaryKey) Then

                        ' If we have less than 11 characters
                        If lcPrimaryKey.Length < 11 Then
                            lnPrimaryKeyTemp = Val(lcPrimaryKey)

                            ' If this is under or equal 2147483647
                            If lnPrimaryKeyTemp <= 2147483647 Then
                                lnPrimaryKey = lnPrimaryKeyTemp
                            Else
                                oProcess.RedirectMain(oProcess.cHttp)
                                Return 0
                            End If

                        Else
                            oProcess.RedirectMain(oProcess.cHttp)
                            Return 0
                        End If

                    Else
                        oProcess.RedirectMain(oProcess.cHttp)
                        Return 0
                    End If

                Else
                    oProcess.RedirectMain(oProcess.cHttp)
                    Return 0
                End If

            End If

            Return lnPrimaryKey
        End Function

I also like it like that as I can negotiate with it in any way I want and follows the path of the framework to not use too much of in-dept functionality of the .NET Framework as it makes it much difficult to migrate to another environment after.