Question

How can I convert SQL time using a datetime stamp to milliseconds.
I am doing a highstock chart using VB.Net

and this is my selection code so far

    Dim mydatalist As New List(Of XyData)
    Dim sqlReader As SqlDataReader
    Dim strConn As New     SqlConnection(ConfigurationManager.ConnectionStrings("myCipConnection").ConnectionString)
    Dim strSql As String = "SELECT TOP 1000 DATEDIFF(second,{d '1970-01-  01'},dtmStamp)AS dtmStamp  ,dblReturnTemp  FROM tblCIPEventData  "
    Dim sqlCmd As New SqlCommand(strSql, strConn)
    strConn.Open()
    sqlReader = sqlCmd.ExecuteReader

I have a SQL selection

Dim strSql As String = "SELECT TOP 1 dtmStamp ,dblReturnTemp   FROM tblCIPEventData"

The result looks like

2009-10-22 11:29:31.513

How can I convert this to milliseconds

Answer 1

To figure out the milliseconds of a date you first have to compare it to some other DateTime. By subtracting two DateTime objects you will end up with a TimeSpan object. Then that TimeSpan object can be converted to milliseconds. This can all be done with one simple line of code:

Dim milliseconds As Double
milliseconds = (end - start).TotalMilliseconds