bind multidimensional array of string into dropdownlist?

I have web service contains some data in json format. I need to get the data into string and bind with the dropdownlist. I need to do it in multidimensional array of string. I tried but dropdownlist didn't populate the data.

Here is the code:

Dim service As New WebSocieties.w_society_detail

                Dim wb As New web_society.w_society_detail

                Dim str_society__type, str_society As String

                str_society__type = wb.mp_society_type("nic", "MPCOOP")

                Dim array_society_type As String() = str_society__type.Split("}"c)

                Dim matrix As [String]()() = New [String](array_society_type.Length - 1)() {}

                For i As Integer = 0 To array_society_type.Length - 1

                    matrix(i) = array_society_type(i).Split(","c)

                    ddlSocieties.Items.Add(matrix(i).ToString)

                Next

ddlSocieties.DataBind()

but Dropdownlist populated system.string[]. Can anyone tell where is the mistake.