How to Hide Certain Tags While Using Linq to Write XML?
Public Class frm
        Public Type As String
        Public RowNumber As Integer
        Public Col1 As String
        Public Col2 As String
  End Class

  Dim bVisCustom2x7 As Boolean

  Dim visform = <VisitorForm>
                      <Tabs>
                           <Tab>
                                  <Type>Custom2x7</Type>
                                  <Order></Order>
                                  <Visibility><%= bVisCustom2x7.ToString %></Visibility>
                                  <%= From frm In frm_list Where frm.Type = "Custom2x7" _
                                      Select _
                                      <Row>
                                          <RowNumber><%= frm.RowNumber %></RowNumber>
                                          <Col1><%= frm.Col1 %></Col1>
                                          <Col2><%= frm.Col2 %></Col2>
                                      </Row>
                                  %>
                             </Tab>
                         <Tabs>
                  <VisitorForm>

<Row>
    <RowNumber><%= frm.RowNumber %></RowNumber>
    <%= If(Not String.IsNullOrEmpty(frm.Col1), <Col1><%= frm.Col1 %></Col1>, Nothing) %>
    <Col2><%= frm.Col2 %></Col2>
</Row>