Change format of value in line chart

hi guys,

I have generated LINE CHART by referring below URL:

http://www.aspsnippets.com/Articles/ASPNet-AJAX-Line-Chart-Control-Populate-from-Database-example.aspx

I just wonder how can i change format of value to ##,0.00

Below is my code

Dim x As String() = New String(DT.Rows.Count - 1) {}
Dim y As Decimal() = New Decimal(DT.Rows.Count - 1) {}

For i As Integer = 0 To DT.Rows.Count - 1
    x(i) = Format(CDate(DT.Rows(i).Item("posting_date")), "dd-MMM-yy")y(i) = Format(Convert.ToDouble(DT.Rows(i).Item("total")), "##,0.00")
Next

LineChart1.Series.Add(New AjaxControlToolkit.LineChartSeries() With {.Name = "MYR", .Data = y})
LineChart1.CategoriesAxis = String.Join(",", x)