Try to pass a querystring with a Class that filters by category

I have one that can get all of the products but i dont know how to filter things by category but its not working can anyone see a problem with my code...

Public Class Products
     Public Function ProductCategory(ByVal maximumRows As Integer, ByVal startRowIndex As Integer, ByVal prodCategory As String) As List(Of Products)
        Dim cn As New SqlConnection(cnString)
        Dim prod As New MaxxProducts()
        cn.Open()
        Dim cm As New SqlCommand
        Dim da As New SqlDataAdapter(cm)
        With cm
            .Connection = cn
            .CommandType = CommandType.StoredProced ...