convertunits.asmx

asp入门到精通的源代码

<%@ WebService Language="VB" Class="ConvertUnits" %>

Imports System
Imports System.Web.Services

public Class ConvertUnits : Inherits WebService
   
   '**********************************************************
   ' Convert: Assumes that the incoming value is of unit
   ' millimeter, and converts to strTo. 
   ' Then passes converted value to ConvertTo function, which
   ' corrects for the unit that was actually passed in    
   ' ie dblValue=10, strFrom=yd, strTo=in, 
   ' answer = 10mm=>inches = 10/25.4 = .394 inches
   '**********************************************************
   <WebMethod(Description:="Converts values to and from a " & _
      "specified unit of measure", EnableSession:=false)> _
      Public Function Convert(dblValue As Double, _
      strFrom as String, strTo as String) As Double
       
      select case strTo
         case "mm"
            Return ConvertTo(dblValue/1, strFrom)
         case "cm"
            Return ConvertTo(dblValue/10, strFrom)
         case "in"
            Return ConvertTo(dblValue/25.4, strFrom)
         case "ft"
            Return ConvertTo(dblValue/304.8, strFrom)
         case "m"
            Return ConvertTo(dblValue/1000, strFrom)
         case "yd"
            Return ConvertTo(dblValue/914.4, strFrom)
         case "mi"
            Return ConvertTo(dblValue/1609344, strFrom)
         case "km"
            Return ConvertTo(dblValue/1000000, strFrom)
         case else
            return 0.0
     end select 
   End Function
   
   '**********************************************************
   ' ConvertTo: Receives a value from Convert, and adjusts
   ' for strFrom. 
   ' We can do this because Convert assumed that incoming
   ' value was millimeter, so we can just alter the value
   ' depending on what the incoming unit actually was
   ' ie dblValue=26.7, strFrom=cm, 
   ' answer = cm=>mm = 26.7*10 = 267 
   ' try it, it really does work!
   '**********************************************************
   Private Function ConvertTo(dblValue as double, _
      strFrom as string) as double
      
      Select case strFrom
         case "mm"
            return dblValue * 1
         case "cm"
            return dblValue * 10
         case "in"
            return dblValue * 25.4
         case "ft"
            return dblValue * 304.8
         case "m"
            return dblValue * 1000
         case "yd"
            return dblValue * 914.4
         case "mi"
            return dblValue * 1609344
         case "km"
            return dblValue * 1000000
         case else
            return 0.0
      End Select
   End Function
   
End Class