ASP.net manipulating data table bound to GridView

Hi. I am running the following code through a button click. It uses the xSQLTable_Suppliers data table declared at the top of the code and bound using the code further down.
For some reason the data table isn't there. It looks like the variable isn't working. The error that I get is that there is no column called "SupplierName"

    Sub Get_Defaults_for_Supplier(ByVal oSupplierName As String)

        xSQLTable_Suppliers.DefaultView.RowFilter = "SupplierName='" & SQLConvert(oSupplierName) & "'"
...


    Dim xSQLAdapter_Suppliers As SqlDataAdapter 'declared at top of webform code
    Dim xSQLTable_Suppliers As New DataTable

    Function Fill_DGV_Suppliers() As Boolean
        Try
            Dim sSQL As String

            sSQL = "Select * From Suppliers"

            Dim connection As New SqlConnection(Session("MyVar"))
            xSQLAdapter_Suppliers = New SqlDataAdapter(sSQL, connection)
            xSQLAdapter_Suppliers.Fill(xSQLTable_Suppliers)
            Me.dgvSuppliers.DataSource = xSQLTable_Suppliers
            Me.dgvSuppliers.DataBind()

            Fill_DGV_Suppliers = True
        Catch ex As Exception
            Me.lblGeneralError.Text = "Problem loading Suppliers table from SQL " & ex.Message
            Fill_DGV_Suppliers = False
        End Try
    End Function