using converters

Question

I have to format a string ("00:10:08:10") into (10 weeks 08 days 10 hrs). So I used a converter and added it with the datagrid binding. My code:

  Public Function Convert(ByVal value As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.Convert
    Dim strList(4) As String
    Dim prefixList() As String = {"Wk", "Dy", "Hrs", "Min"}
    Dim input As String = value.ToString
    Dim Output As String = String.Empty
    If input <> String.Empty Then
        strList = input.Split(":")
        Dim itr As Integer
        For Each Str As String In strList
            If Integer.Parse(Str) <> 0 Then
                Output += Str + " " + prefixList(itr) + " "
            End If
            itr += 1
        Next
    End If
    Return Output
End Function

I am getting it converted but when I edit the data, the converter is called again where I wouldn't have the old format("00:10:08:10") and instead its (10 Dy 08 Hr 10 Min). so the converter fails obviously. How can I make it work?

Additional: And is there a data type in mssql to represent my data in days and hours so that i wont have to use this string format.

Answer 1

You need to implement the ConvertBack function in your ValueConverter to convert from 10 Dy 08 Hr 10 Min to 00:10:08:10.

Assuming the string is in the correct format, it shouldn't be too difficult to parse and convert.

You might consider using a timespan to hold the data. It stores a length of time or duration.

Answer 2

About the additional: I always use timestamps (milliseconds since 1/1/1970) when storing times in sql. They are very easy to sort and can be parsed to and from DateTime object (or similar) in almost every programming language.