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我有一个在 Visual Studio 2010 中使用 vb.net 创建的 .asmx Web 服务。我最近修改了下面的查询并添加了“, geography::Point(@Latitude, @Longitude, 4326).STDistance(Location) * 0.00062137119”。由于我添加了我需要添加到 while reader.Read() 循环以将小数作为 web 服务的 xml 上的字符串输出 linefuelStop.Distance = reader.GetString(5) 显然不起作用我该怎么办输出到xml的距离？

网络服务代码：

<WebMethod()> _
Public Function GetFuelStops(ByVal Latitude As Double, ByVal Longitude As Double) As FuelStop()
    Dim resultList = New List(Of FuelStop)()

    Using sqlCon As New SqlConnection()
        sqlCon.ConnectionString = "Data Source=(local);Initial Catalog=My_DB;User ID=*****;Password=*******"
        Dim sql = <sql>
            DECLARE @center GEOGRAPHY

            SET @center = geography::Point(@Latitude, @Longitude, 4326)

            SELECT TOP 10
                [Physical_Address_Street]
                , [Physical_Address_Local]
                , [Physical_Address_State]
                , [Physical_Address_Zip]
                , [Phone_Number]
                , geography::Point(@Latitude, @Longitude, 4326).STDistance(Location) * 0.00062137119
            FROM Gas_Stations
            WHERE Location_Type = 1
            ORDER BY @center.STDistance(Location) ASC
            </sql>
        Dim command As New SqlCommand()
        command.CommandText = CStr(sql)
        command.Parameters.Add("@Latitude", SqlDbType.Decimal).Value = Latitude
        command.Parameters.Add("@Longitude", SqlDbType.Decimal).Value = Longitude
        command.Connection = sqlCon
        sqlCon.Open()

        Using reader = command.ExecuteReader()
            While reader.Read()
                Dim fuelStop = New FuelStop()
                fuelStop.Physical_Address_Street = reader.GetString(0)
                fuelStop.Physical_Address_Local = reader.GetString(1)
                fuelStop.Physical_Address_State = reader.GetString(2)
                fuelStop.Physical_Address_Zip = reader.GetString(3)
                fuelStop.Phone_Number = reader.GetString(4)
                fuelStop.Distance = reader.GetString(5)



                resultList.Add(fuelStop)
            End While
        End Using
    End Using
    Return resultList.ToArray()

End Function

这是我的 FuelStop.class

Public Class FuelStop

    Property Physical_Address_Street As String

    Property Physical_Address_Local As String

    Property Physical_Address_State As String

    Property Physical_Address_Zip As String

    Property Phone_Number As String

    Property Distance As String

End Class
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1 回答 1

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您正在尝试将浮点数作为字符串读取，您应该使用正确的类型从阅读器中获取它：

reader.GetDecimal(5)

并将正确的类型放入要返回的类中。

（正如评论中所确定的，您发现它 Double 可以工作:)）

字符串以外的东西的序列化在 XML 中仍然会正确显示（大部分情况下）。

于 2013-04-26T15:32:38.713 回答