Problem passing an instantiated class as a subroutine parameter

public class Filters       // found in namespace SQLClass
{
    public Filters()
   {
        FirstNameFilter = "";
        LastNameFilter = "";
        AddressFilter = "";
        CityFilter = "";
        ZipCodeFilter = "";
    }

    public string FirstNameFilter { get; set; }
    public string LastNameFilter { get; set; }
    public string AddressFilter { get; set; }
    public string CityFilter { get; set; }
    public string ZipCodeFilter { get; set; }
}

        private void FrmMain_Load(object sender, EventArgs e)
        {
            CenterToParent();
            Filters ListFilters = new SQLClass.Filters();
            PopulateListView(ListFilters, "Last Name/First Name/City/Address");
// The above line gets error "Argument 1: Cannot convert from 'SQLClass.Filters' to 'ListFilters'"
        }

private void PopulateListView(ListFilters>, string OrderBy)
// The above line gets error "The type or namespace name 'ListFilters' could not be found (are you missing a using directive or an assembly reference?)"
        {
            SQLDatabase MySQLClass = new SQLDatabase();

            string TheDatabase = "CustomerDB";
            string TheProcedure = "usp_GetCustomers";
            Dictionary<string, ParameterValues> TheParams = new Dictionary<string, ParameterValues>();

            ParameterValues values = new ParameterValues();

            values = new ParameterValues(); values.Value = ListFilters.FirstNameFilter; values.Direction = "Input"; 
// The above line gets error "The name 'ListFilters' does not exist in the current context"
TheParams.Add("@parmFirstName", values);
            values = new ParameterValues(); values.Value = ListFilters.LastNameFilter; values.Direction = "Input"; TheParams.Add("@parmLastName", values);
            values = new ParameterValues(); values.Value = ListFilters.AddressFilter; values.Direction = "Input"; TheParams.Add("@parmAddress", values);
            values = new ParameterValues(); values.Value = ListFilters.CityFilter; values.Direction = "Input"; TheParams.Add("@parmCity", values);
            values = new ParameterValues(); values.Value = ListFilters.ZipCodeFilter; values.Direction = "Input"; TheParams.Add("@parmZipCode", values);
            values = new ParameterValues(); values.Value = OrderBy; values.Direction = "Input"; TheParams.Add("@parmOrderBy", values);