New Post: Creating Legend in VB.net

It helps a lot, thanks a lot, Pein.

I figured the part

Dim index As Integer = sf.Table.FieldIndexByName("IDPROV")
sf.Categories.Generate(index, MapWinGIS.tkClassificationType.ctEqualIntervals, NumericUpDown1.Value)

can only read index from the DBF, so I matched the IDPROV of DBF and MDB, like your sample above, then copy the SEXRATIO data from MDB to the DBF so that I could call the index to create categories from it.

        Connection()
        Dim dbcommandc As New OleDbCommand("SELECT * FROM DATA_PROV", conn) 'DATA_PROV is the name of the table in MDB
        Dim dbDRc As OleDb.OleDbDataReader = dbcommandc.ExecuteReader

        Dim idFld As New MapWinGIS.Field
        idFld.Name = "SEXRATIO"
        idFld.Type = MapWinGIS.FieldType.DOUBLE_FIELD
        idFld.Width = 8
        sf.StartEditingTable()
        sf.EditInsertField(idFld, sf.Table.NumFields)

        Dim i  As Integer = 0
        Do While dbDRm.Read
            If dbDRc("IDPROV") = sf.Table.CellValue(sf.Table.FieldIndexByName("IDPROV"), i) Then
            sf.Table.EditCellValue(sf.Table.FieldIndexByName("SEXRATIO"), i, dbDRm("SEXRATIO"))
            i = i + 1
        Loop

        sf.StopEditingTable(True)

So far it works well. I can use the SEXRATIO data to create categories.
Thank you, Pein.