Sets or returns an int that represents the line numbering modulus. This setting is used to set whether line numbers display on every line, every 2nd line, etc. Setting this to 0 (zero) will display no line numbers. Setting this to 1 will display a number by every line. Setting this to 2 will display a number by every 2nd line, etc.

 public int LineNumModulus{ get; set; }
Public Property LineNumModulus() As Integer

MS Word equivalent: File > Page Setup... > Layout tab > Preview section (make sure Apply To: This Section is selected) > Line Numbers... button > Count by:

          //--- Return LineNumModulus
          int lineNumModulus = oSection.LineNumModulus;

          //--- Set LineNumModulus
          oSection.LineNumModulus = 2;

          '--- Return LineNumModulus
          Dim lineNumModulus As Integer = oSection.LineNumModulus

          '--- Set LineNumModulus
          oSection.LineNumModulus = 2