How to write/ return URL with parameter in .aspx.vb page

I an new learner of asp.net and vb.net. I am trying to convert .aspx lines of code into .aspx.vb code 

The following two lines of URL making code  are now written in .aspx page. I want to write these lines of code  in .aspx.vb    page. 

 .aspx page

<%= Employer.CareersUrl%>?_mj=<%= Vacancy.ID & "-" & Vacancy.Title.Replace(" ", "-")%> <br/> http://cs.mypbiz.com<%= Microsite.AppRelativeBaseUrl.TrimStart("~")%>/<%=Vacancy.ID%>-<%= Helper.TruncateString(Vacancy.Title.Replace(" ", "-"), 30, "")%>.aspx 

I want to write these above two lines of URL making code  in .aspx.vb page like the following line

    Private Function MakeUrl(ByVal vacancy As Vacancy) As String
               If Not String.IsNullOrWhiteSpace(Employer.CareersUrl) Then

                     'Return Helper.ResolveUrL("~/candidate/jobs/detail.aspx?vacancy=" & vacancy.ID & "&utm_source=RSS+link+backs&utm_medium=RSS&utm_campaign=RSS")
               ElseIf Not IsNothing(Microsite) Then
                      Return ("portals.mypbiz.com/candidate/jobs/detail.aspx?vacancy=" & vacancy.ID & "&utm_source=RSS+link+backs&utm_medium=RSS&utm_campaign=RSS")

               End If


    End Function

I have written necessary property and function in the aspx.vb file to inherit the class behaviour . but not being able to  write URL properly. 

Forgive my ignorance. I know very little of asp.net and vb.net coding