VB.NET method for dropdownlist binding

 Public Shared Sub combofill(ByVal cmm As SqlCommand, ByVal dropdown As DropDownList, ByVal valuefield As String, ByVal textfield As String)
        dropdown.Items.Clear()
        Dim dt As DataTable
        dt = DataConnect.GetInstance.GetDt(cmm)
        dt.TableName = "dt"
        Dim dr As DataRow
        dr = dt.NewRow()
        dr(valuefield) = 0
        dr(textfield) = "Select"
        dt.Rows.Add(dr)
        dt.AcceptChanges()

        Dim dw As New DataView
        dw = New DataView
        dw.Table = dt
        dw.Sort = valuefield & " asc"

        dropdown.DataSource = dw
        dropdown.DataTextField = textfield
        dropdown.DataValueField = valuefield
        dropdown.DataBind()

        dropdown.SelectedValue = 0
        dropdown.DataSource = dw
        dropdown.DataTextField = textfield
        dropdown.DataValueField = valuefield
        dropdown.DataBind()
        dropdown.SelectedValue = 0
    End Sub